`bzr send` does not work on treeless branch

[IWATA Hidetaka]

In bzr2.5b5, 'bzr send' does not work on the treeless branch.
2.5b4 works well.

This also affects to qsend command.
qsend does not work not only when executed on the treeless branch but also on the lightweight checkout.

--
This command results following traceback::
  bzr send /path/to/submit/branch -f /path/to/treeless/branch -o foo.patch

bzr: ERROR: exceptions.AttributeError: 'NoneType' object has no attribute 'bzrdir'

Traceback (most recent call last):
  File "C:\DEVELOP\py_envs\bzr2.5-mingw\lib\site-packages\bzrlib\commands.py", line 919, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "C:\DEVELOP\py_envs\bzr2.5-mingw\lib\site-packages\bzrlib\commands.py", line 1124, in run_bzr
    ret = run(*run_argv)
  File "C:\DEVELOP\py_envs\bzr2.5-mingw\lib\site-packages\bzrlib\commands.py", line 672, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "C:\DEVELOP\py_envs\bzr2.5-mingw\lib\site-packages\bzrlib\commands.py", line 694, in run
    return self._operation.run_simple(*args, **kwargs)
  File "C:\DEVELOP\py_envs\bzr2.5-mingw\lib\site-packages\bzrlib\cleanup.py", line 136, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "C:\DEVELOP\py_envs\bzr2.5-mingw\lib\site-packages\bzrlib\cleanup.py", line 166, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "C:\DEVELOP\py_envs\bzr2.5-mingw\lib\site-packages\bzrlib\builtins.py", line 5745, in run
    strict=strict)
  File "C:\DEVELOP\py_envs\bzr2.5-mingw\lib\site-packages\bzrlib\send.py", line 46, in send
    possible_transports = [tree.bzrdir.transport, branch.bzrdir.transport]
AttributeError: 'NoneType' object has no attribute 'bzrdir'

bzr 2.5b5 on python 2.7.2 (Windows-7-6.1.7601-SP1)
arguments: ['C:\\DEVELOP\\py_envs\\bzr2.5-mingw\\Scripts\\bzr', 'send',
    'colo:origin/trunk', '-f', 'colo:qdiff-refactor', '-o', 'test.patch']
plugins: bash_completion[2.5b5], changelog_merge[2.5b5], colo[0.2.1],
    explorer[1.2.0dev], launchpad[2.5b5], netrc_credential_store[2.5b5],
    news_merge[2.5b5], po_merge[2.5b5], qbzr[0.22.0dev], recommit[unknown],
    rewrite[0.6.2dev], rewrite_interactive[unknown], weave_fmt[2.5b5],
    xmloutput[0.8.8]
encoding: 'cp932', fsenc: 'mbcs', lang: 'ja'