[win32] Permission denied in fancy_rename

[Alexander Belchenko]

Some of selftests fails on windows native due to permissions denied 
error. And almost all of them raise this error in fancy_rename function 
from osutils module.

I think most of this errors raise because in bzrlib used linux approach 
to do not close explicitly files after read/write operations and rely on 
unlink functionality of linux. Unfortunately unlink does not exist on 
windows and windows itself cannot delete file in use.

Today I pulling branch of Bugs Everywhere of Aaron Bentley. I try to 
pull this branch into knit format otherwise it fails due to 
incompatibility with some filenames. After pull bzr breaks with the same 
error:

E:\work\Python\bzr\third.party\be>bzr pull 
http://panoramicfeedback.com/opensource/bzr/be
Backup Inventory created.
bzr: ERROR: exceptions.OSError: [Errno 13] Permission denied
   at E:\work\Python\bzr\bzr.dev\bzrlib\osutils.py line 143
   in fancy_rename

When I switch to cygwin I can finish this pull successfully.

Dear core developers! Don't leave files opened after use! Please, close 
them explicitly! Or bzr always has minor issues on windows platform.

Thank you.

--
Alexander