Fixed #7572 -- Force the closure of the database connection at the end of  fixture loading as a workaround for MySQL bug #37735. Thanks to Simon Litchfield for his help in narrowing down this issue.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@7803 bcc190cf-cafb-0310-a4f2-bffc1f526a37