Fixed #14046 -- Made {% include %} behave the same, regardless of whether the template included is named by variable or constant string. Thanks to defcube for the report, and George Karpenkov for the draft patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@15413 bcc190cf-cafb-0310-a4f2-bffc1f526a37