Problem if branch already exists

[Jono Bacon]

If an existing branch exists, Ground Control blows up with fileexists errors. From groundcontrol.log:

02-07 19:47 root ERROR File exists: u'/home/jono/Projects/groundcontrol/bugfix-lp-518545/.bzr': [Errno 17] File exists: '/home/jono/Projects/groundcontrol/bugfix-lp-518545/.bzr'
Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/GroundControl/base.py", line 73, in run
    super(Thread, self).run(*args, **kwargs)
  File "/usr/lib/python2.6/threading.py", line 479, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/usr/lib/python2.6/dist-packages/GroundControl/bazaar.py", line 310, in inital_thread
    self.do_action()
  File "/usr/lib/python2.6/dist-packages/GroundControl/bazaar.py", line 387, in do_action
    branched = self.branch.branch.bzrdir.sprout(dest_dir).open_branch()
  File "/usr/lib/python2.6/dist-packages/bzrlib/bzrdir.py", line 1151, in sprout
    result = cloning_format.initialize_on_transport(target_transport)
  File "/usr/lib/python2.6/dist-packages/bzrlib/bzrdir.py", line 1863, in initialize_on_transport
    return self._initialize_on_transport_vfs(transport)
  File "/usr/lib/python2.6/dist-packages/bzrlib/bzrdir.py", line 1984, in _initialize_on_transport_vfs
    mode=temp_control._dir_mode)
  File "/usr/lib/python2.6/dist-packages/bzrlib/transport/local.py", line 325, in mkdir
    self._mkdir(self._abspath(relpath), mode=mode)
  File "/usr/lib/python2.6/dist-packages/bzrlib/transport/local.py", line 321, in _mkdir
    self._translate_error(e, abspath)
  File "/usr/lib/python2.6/dist-packages/bzrlib/transport/__init__.py", line 314, in _translate_error
    raise errors.FileExists(path, extra=e)
FileExists: File exists: u'/home/jono/Projects/groundcontrol/bugfix-lp-518545/.bzr': [Errno 17] File exists: '/home/jono/Projects/groundcontrol/bugfix-lp-518545/.bzr'
02-07 19:47 root DEBUG -- Poll Quit status_window --
02-07 19:47 root DEBUG Canceled or No Callback for Window
02-07 19:47 root DEBUG Quit 'status_window' Main Loop.
02-07 19:47 root DEBUG Transporting from '/home/jono/Projects/groundcontrol/bugfix-lp-518545'
02-07 19:47 root DEBUG Quit 'bug_search' Main Loop.
02-07 19:48 root DEBUG Loaded project groundcontrol
02-07 19:48 root DEBUG Loaded project groundcontrol
02-07 19:48 root DEBUG Transporting from '/home/jono/Projects/groundcontrol/bugfix-lp-518545'
02-07 19:48 root DEBUG Loaded project groundcontrol
02-07 19:48 root DEBUG Loaded project groundcontrol
02-07 19:48 root DEBUG Transporting from '/home/jono/Projects/groundcontrol/groundcontrol'