Fixed #17737 -- Stopped the collectstatic management command from copying the...

Fixed #17737 -- Stopped the collectstatic management command from copying the wrong file in repeated runs. Thanks, pigletto.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@17612 bcc190cf-cafb-0310-a4f2-bffc1f526a37