Migration test locking is broken

Fix proposed to branch: master
Review: https://review.openstack.org/58830

This is copied from http://logs.openstack.org/16/56516/13/check/gate-ironic-python26/c7798a4/testr_results.html.gz
Showing the detail:

ft1.304: ironic.tests.db.sqlalchemy.test_migrations.TestMigrations.test_postgresql_opportunistically_StringException: Empty attachments:
  pythonlogging:'ironic.openstack.common'
  stderr
  stdout

traceback-1: {{{
Traceback (most recent call last):
  File "ironic/openstack/common/db/sqlalchemy/test_migrations.py", line 160, in tearDown
    self._reset_databases()
  File "ironic/openstack/common/db/sqlalchemy/test_migrations.py", line 218, in _reset_databases
    self._reset_pg(conn_pieces)
  File "ironic/openstack/common/db/sqlalchemy/test_migrations.py", line 105, in wrapper
    with lock:
  File "/home/jenkins/workspace/gate-ironic-python26/.tox/py26/lib/python2.6/site-packages/lockfile/__init__.py", line 226, in __enter__
    self.acquire()
  File "/home/jenkins/workspace/gate-ironic-python26/.tox/py26/lib/python2.6/site-packages/lockfile/linklockfile.py", line 20, in acquire
    raise LockFailed("failed to create %s" % self.unique_name)
LockFailed: failed to create /home/jenkins/workspace/gate-ironic-python26/pgadmin/centos6-5.slave.openstack.org-4134c700.6738
}}}

Traceback (most recent call last):
  File "ironic/tests/db/sqlalchemy/test_migrations.py", line 296, in test_postgresql_opportunistically
    self._test_postgresql_opportunistically()
  File "ironic/tests/db/sqlalchemy/test_migrations.py", line 275, in _test_postgresql_opportunistically
    self._reset_databases()
  File "ironic/openstack/common/db/sqlalchemy/test_migrations.py", line 218, in _reset_databases
    self._reset_pg(conn_pieces)
  File "ironic/openstack/common/db/sqlalchemy/test_migrations.py", line 105, in wrapper
    with lock:
  File "/home/jenkins/workspace/gate-ironic-python26/.tox/py26/lib/python2.6/site-packages/lockfile/__init__.py", line 226, in __enter__
    self.acquire()
  File "/home/jenkins/workspace/gate-ironic-python26/.tox/py26/lib/python2.6/site-packages/lockfile/linklockfile.py", line 20, in acquire
    raise LockFailed("failed to create %s" % self.unique_name)
LockFailed: failed to create /home/jenkins/workspace/gate-ironic-python26/pgadmin/centos6-5.slave.openstack.org-4134c700.6738

Reviewed: https://review.openstack.org/58830
Committed: http://github.com/openstack/oslo-incubator/commit/4c47d3e759f15f1f3b230323ca723fbb1dd90a4f
Submitter: Jenkins
Branch: master

commit 4c47d3e759f15f1f3b230323ca723fbb1dd90a4f
Author: Ben Nemec <email address hidden>
Date: Wed Nov 27 17:41:25 2013 +0000

    Fix locking in migration tests

    The migration test code included an external lock with a hard-coded
    relative path that breaks when run in Jenkins. It wasn't being hit
    in Oslo because it was only locking for the postgres code path,
    which isn't currently tested in Oslo.

    This change moves the lock so that it applies to all db types and
    removes the relative path. For the locks to work properly it was
    also necessary to add the lockutils wrapper to the Oslo tox.ini.

    Closes-Bug: 1255608
    Change-Id: I333b833022f208e48e3b7e82e8cfad2764be5ea0