Fixed an error in the `firstof` template tag when used with `TEMPLATE_STRING_IF_INVALID`. Thanks to Alex Gaynor for the patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@10124 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/template/defaulttags.py

@@ -74,7 +74,7 @@ class FirstOfNode(Node):
 
     def render(self, context):
         for var in self.vars:
-            value = var.resolve(context)
+            value = var.resolve(context, True)
             if value:
                 return smart_unicode(value)
         return u''