Fixed #6273 -- Added a 'changepassword' management command. Thanks to Ludvig...

Fixed #6273 -- Added a 'changepassword' management command. Thanks to Ludvig Ericson and Justin Lilly for their work on this patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@12351 bcc190cf-cafb-0310-a4f2-bffc1f526a37