Fixed #8900: Added errno=13 (permission denied) to the class of ignored...

Fixed #8900: Added errno=13 (permission denied) to the class of ignored OSErrors when attempting to delete the old file in file_move_safe.

This error was seen on Windows with Pythons < 2.5.  In the case where the error was seen, the old file is auto-deleted on close anyway by the Windows-specific NamedTemporaryFile support.

No new test because the failure could be seen when running the file_uploads test with Python 2.3/2.4 on Windows.  With this fix file_uploads runs clean in that environment.

While in the neignborhood fixed up the docstrings to better match the reality of what the code does and what the function is named.



git-svn-id: http://code.djangoproject.com/svn/django/trunk@10396 bcc190cf-cafb-0310-a4f2-bffc1f526a37