Updated mediawiki/extensions
Project: mediawiki/extensions/MobileFrontend  a9233b55d633d8415e747420fb785399a5aa7822

Regression: Fix PageApi for non-existent pages

It would throw an error which made Talk overlays fail when there was no
discussions.

Change-Id: I72f63ce45388c4322fcfa05fbe7236bf52262235