[Bug] bzr selftest cleanup is broken on win32 (again)

[Alexander Belchenko]

Alexander Belchenko пишет:
> Here is result of running selftest on win32 with fresh bzr.dev revno.1982
> 
> Ran 3329 tests in 1727.695s
> 
> FAILED (failures=33, errors=41)

Too many tests have similar error messages:

======================================================================
ERROR: test_external_diff (bzrlib.tests.test_diff.TestDiff)

vvvv[log from
bzrlib.tests.test_diff.TestDiff.test_external_diff]-------------

^^^^[log from
bzrlib.tests.test_diff.TestDiff.test_external_diff]-------------
----------------------------------------------------------------------
Traceback (most recent call last):
   File "D:\Bazaar\sandbox\bzr.dev\bzrlib\tests\test_diff.py", line 101,
in test_external_diff
     lines = external_udiff_lines(['boo\n'], ['goo\n'])
   File "D:\Bazaar\sandbox\bzr.dev\bzrlib\tests\test_diff.py", line 44,
in external_udiff_lines
     external_diff('old', old, 'new', new, output, diff_opts=['-u'])
   File "D:\Bazaar\sandbox\bzr.dev\bzrlib\diff.py", line 185, in
external_diff
     pipe = _spawn_external_diff(diffcmd, capture_errors=True)
   File "D:\Bazaar\sandbox\bzr.dev\bzrlib\diff.py", line 117, in
_spawn_external_diff
     preexec_fn=preexec_fn)
   File "E:\Python24\lib\subprocess.py", line 497, in __init__
     raise ValueError("preexec_fn is not supported on Windows "
ValueError: preexec_fn is not supported on Windows platforms

==============================================================================

This meant that external diff couldn't be used on Windows with current
bzr.dev.

--
Alexander