Fixed #14921 -- Tweak changes made in r14861 for the Oracle backend so the...

Fixed #14921 -- Tweak changes made in r14861 for the Oracle backend so the test runner can actually create the test DB. Thanks Karen for the report.

In Oracle, the name of a DB as handled by Django hasn't a counterpart anyway. So use the 'production DB name' as it was done before.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@14993 bcc190cf-cafb-0310-a4f2-bffc1f526a37