Fix fatal

PHP Fatal error:  Call to a member function getLocalUrl() on a
non-object in /usr/local/apache/common-local/php-1.23wmf4/extensions/MobileFrontend/includes/specials/SpecialHistory.php
on line 94

Change-Id: I9c1a22ae12dee022254453ad6f931398d4c5a232
(cherry picked from commit 160013d74367a4f7c3407986493008f437b64211)