Recent fix to integration tests didn't fix the intermittent test_dashboard_help_redirection failure

A watchful reviewer may notice that sometimes test_dashboard_help_redirection fails. Initially I thought that it was caught by an increased network timeout from Jenkins worker node to docs.openstack.org site. So I made a patch https://github.com/openstack/horizon/commit/6474215840d4cdde3751c335f46f32cb317238c0

Recently I found that this intermittent failure still occurs. This time I reproduced the network delay by means of script (run as root):

delay.sh
<BEGIN OF FILE>
delay=$1
ip=$2

tc qdisc del dev eth0 root
if [ -n $delay ]; then
    tc qdisc add dev eth0 root handle 1: prio
    tc filter add dev eth0 parent 1:0 protocol ip pref 55 handle ::55 u32 match ip dst $ip flowid 2:1
    tc qdisc add dev eth0 parent 1:1 handle 2: netem delay ${delay}ms
fi
<END OF FILE>

I realized that first the window is opened, then it waits for the page to become accessible, and if I set timeout large enough (say, 10 seconds), I get the following traceback:

Error
Traceback (most recent call last):
  File "/home/timur/develop/horizon/.venv/local/lib/python2.7/site-packages/nose/case.py", line 133, in run
    self.runTest(result)
  File "/home/timur/develop/horizon/.venv/local/lib/python2.7/site-packages/nose/case.py", line 151, in runTest
    test(result)
  File "/home/timur/develop/horizon/.venv/local/lib/python2.7/site-packages/unittest2/case.py", line 673, in __call__
    return self.run(*args, **kwds)
  File "/home/timur/develop/horizon/.venv/local/lib/python2.7/site-packages/testtools/testcase.py", line 606, in run
    return run_test.run(result)
  File "/home/timur/develop/horizon/.venv/local/lib/python2.7/site-packages/testtools/runtest.py", line 80, in run
    return self._run_one(actual_result)
  File "/home/timur/develop/horizon/.venv/local/lib/python2.7/site-packages/testtools/runtest.py", line 94, in _run_one
    return self._run_prepared_result(ExtendedToOriginalDecorator(result))
  File "/home/timur/develop/horizon/.venv/local/lib/python2.7/site-packages/testtools/runtest.py", line 108, in _run_prepared_result
    self._run_core()
  File "/home/timur/develop/horizon/.venv/local/lib/python2.7/site-packages/testtools/runtest.py", line 149, in _run_core
    self.case._run_teardown, self.result):
  File "/home/timur/develop/horizon/.venv/local/lib/python2.7/site-packages/testtools/runtest.py", line 193, in _run_user
    return self._got_user_exception(sys.exc_info())
  File "/home/timur/develop/horizon/.venv/local/lib/python2.7/site-packages/testtools/runtest.py", line 213, in _got_user_exception
    self.case.onException(exc_info, tb_label=tb_label)
  File "/home/timur/develop/horizon/.venv/local/lib/python2.7/site-packages/testtools/testcase.py", line 558, in onException
    handler(exc_info)
  File "/home/timur/develop/horizon/openstack_dashboard/test/integration_tests/helpers.py", line 132, in _save_screenshot
    self.driver.get_screenshot_as_file(filename)
  File "/home/timur/develop/horizon/.venv/local/lib/python2.7/site-packages/selenium/webdriver/remote/webdriver.py", line 758, in get_screenshot_as_file
    png = self.get_screenshot_as_png()
  File "/home/timur/develop/horizon/.venv/local/lib/python2.7/site-packages/selenium/webdriver/remote/webdriver.py", line 777, in get_screenshot_as_png
    return base64.b64decode(self.get_screenshot_as_base64().encode('ascii'))
  File "/home/timur/develop/horizon/.venv/local/lib/python2.7/site-packages/selenium/webdriver/remote/webdriver.py", line 787, in get_screenshot_as_base64
    return self.execute(Command.SCREENSHOT)['value']
  File "/home/timur/develop/horizon/.venv/local/lib/python2.7/site-packages/selenium/webdriver/remote/webdriver.py", line 199, in execute
    response = self.command_executor.execute(driver_command, params)
  File "/home/timur/develop/horizon/.venv/local/lib/python2.7/site-packages/selenium/webdriver/remote/remote_connection.py", line 395, in execute
    return self._request(command_info[0], url, body=data)
  File "/home/timur/develop/horizon/.venv/local/lib/python2.7/site-packages/selenium/webdriver/remote/remote_connection.py", line 425, in _request
    self._conn.request(method, parsed_url.path, body, headers)
  File "/usr/lib/python2.7/httplib.py", line 979, in request
    self._send_request(method, url, body, headers)
  File "/usr/lib/python2.7/httplib.py", line 1013, in _send_request
    self.endheaders(body)
  File "/usr/lib/python2.7/httplib.py", line 975, in endheaders
    self._send_output(message_body)
  File "/usr/lib/python2.7/httplib.py", line 835, in _send_output
    self.send(msg)
  File "/usr/lib/python2.7/httplib.py", line 797, in send
    self.connect()
  File "/usr/lib/python2.7/httplib.py", line 778, in connect
    self.timeout, self.source_address)
  File "/usr/lib/python2.7/socket.py", line 571, in create_connection
    raise err
error: [Errno 111] Connection refused

It's different from the traceback that follows intermittent failure on gate:

2015-11-24 19:48:29.619 | 2015-11-24 19:48:29.606 | Traceback (most recent call last):
2015-11-24 19:48:29.620 | 2015-11-24 19:48:29.607 | File "/opt/stack/new/horizon/openstack_dashboard/test/integration_tests/tests/test_dashboard_help_redirection.py", line 28, in test_dashboard_help_redirection
2015-11-24 19:48:29.621 | 2015-11-24 19:48:29.608 | "help link did not redirect to the right URL")
2015-11-24 19:48:29.623 | 2015-11-24 19:48:29.609 | File "/opt/stack/new/horizon/.tox/py27integration/local/lib/python2.7/site-packages/testtools/testcase.py", line 350, in assertEqual
2015-11-24 19:48:29.624 | 2015-11-24 19:48:29.610 | self.assertThat(observed, matcher, message)
2015-11-24 19:48:29.625 | 2015-11-24 19:48:29.611 | File "/opt/stack/new/horizon/.tox/py27integration/local/lib/python2.7/site-packages/testtools/testcase.py", line 435, in assertThat
2015-11-24 19:48:29.626 | 2015-11-24 19:48:29.613 | raise mismatch_error
2015-11-24 19:48:29.627 | 2015-11-24 19:48:29.614 | testtools.matchers._impl.MismatchError: 'http://docs.openstack.org/' != u'http://localhost/dashboard/project/': help link did not redirect to the right URL

The second one looks more like the command to switch the window was issued before window was actually opened. If that's truly the root cause, fix should be trivial.