Possible bug, bzrlib.initialize(setup_ui=False) is broken

[Zygmunt Krynicki]

Hi.

On 2.4.0~beta4-1~bazaar1~natty1

Calling bzrlib.initialize(setu_ui=False) with the intent to use 
SilentUIFactory() is broken. The code goes to initialize with 
BzrLibraryState(ui=None) and immediately calls _start(). This in turn 
calls ui.__enter__() which fails with the following backtrace:

(parts not relevant to bzr were removed)

   File "/home/zyga/Linaro/lava-ci/lava_ci/component.py", line 347, in 
__init__
     self._bzr = initialize(setup_ui=False)
   File "/usr/lib/python2.7/dist-packages/bzrlib/__init__.py", line 185, 
in initialize
     state._start()
   File "/usr/lib/python2.7/dist-packages/bzrlib/library_state.py", line 
93, in _start
     self._ui.__enter__()
AttributeError: 'NoneType' object has no attribute '__enter__'


Best regards
ZK