bzrtools (failed to load) with KeyError: "Key 'fetch-ghosts' already registered"

Bazaar (bzr) 2.7.0dev1
  Python interpreter: /usr/bin/python 2.7.6
  Python standard library: /usr/lib/python2.7
  Platform: Linux-3.13.0-37-generic-i686-with-Ubuntu-14.04-trusty
  bzrlib: /usr/lib/python2.7/dist-packages/bzrlib
  Bazaar configuration: /home/rte/.bazaar
  Bazaar log file: /home/rte/.bzr.log

Ubuntu 14.04.1 LTS

$ pwd
/home/rte/.bazaar/plugins

$ bzr branch --stack lp:bzrtools
<snip>
Created new stacked branch referring to http://bazaar.launchpad.net/~abentley/bzrtools/bzrtools.dev/.

$ bzr plugins
<snip>
bzrtools (failed to load)
  ** Unable to load plugin u'bzrtools' from u'/home/rte/.bazaar/plugins'

$ rm -rf bzrtools/
$ bzr co lp:bzrtools
$ bzr plugins
<snip>
bzrtools (failed to load)
  ** Unable to load plugin u'bzrtools' from u'/home/rte/.bazaar/plugins'

$ cat ~/.bzr.log

this is a debug log for diagnosing/reporting problems in bzr
you can delete or truncate this file, or include sections in
bug reports to https://bugs.launchpad.net/bzr/+filebug

Mon 2014-10-13 02:48:22 -0500
0.061 bazaar version: 2.7.0dev1
0.061 bzr arguments: [u'plugins']
0.065 looking for plugins in /home/rte/.bazaar/plugins
[16687] 2014-10-13 02:48:22.925 WARNING: "Key 'fetch-ghosts' already registered"
0.067 Unable to load plugin u'bzrtools' from u'/home/rte/.bazaar/plugins'
0.068 Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/bzrlib/plugin.py", line 382, in _load_plugin_module
    exec "import bzrlib.plugins.%s" % name in {}
  File "<string>", line 1, in <module>
  File "/home/rte/.bazaar/plugins/bzrtools/__init__.py", line 56, in <module>
    'bzrlib.plugins.bzrtools.command_classes')
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 137, in register_lazy
    info=CommandInfo(aliases))
  File "/usr/lib/python2.7/dist-packages/bzrlib/registry.py", line 151, in register_lazy
    raise KeyError('Key %r already registered' % key)
KeyError: "Key 'fetch-ghosts' already registered"

0.068 looking for plugins in /usr/lib/python2.7/dist-packages/bzrlib/plugins
0.083 encoding stdout as sys.stdout encoding 'UTF-8'
0.091 Transferred: 0kB (0.0kB/s r:0kB w:0kB)
0.091 return code 0