[1.2.X] Fixed #11369 -- Corrected verbose_name_plural model Meta option to be...

[1.2.X] Fixed #11369 -- Corrected verbose_name_plural model Meta option to be consistent with verbose_name when using abstract model inheritance. Thanks Beetle_B for the report.

Backport of [14588] from trunk

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@14589 bcc190cf-cafb-0310-a4f2-bffc1f526a37