[1.0.X] Fixed #10357 -- Fixed the "dbshell" command for Windows users.

Thanks to markshep for the patch.

Backport of r10517 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@10518 bcc190cf-cafb-0310-a4f2-bffc1f526a37