Fixed #14126 -- Fixed an issue with changes to the blocktrans tag introduced...

Fixed #14126 -- Fixed an issue with changes to the blocktrans tag introduced in r13967 related to multiple plural forms. Thanks, mark0978, svetlyak40wt and Ramiro.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@14239 bcc190cf-cafb-0310-a4f2-bffc1f526a37