Remove aborting of BeforePageDisplay hook

Authored by Krinkle on Aug 18 2017, 11:38 PM.

Description

Remove aborting of BeforePageDisplay hook

This caused random extensions to not be able to load any ResourceLoader
modules (or do other things) on a random subset of pages and wikis.

Follows-up 29770a3.

Bug: T173411
Change-Id: I8dfc1085cb7d902f9e9be8a71324dc4cd850a500
(cherry picked from commit 55f075bf11326bb29b162c958de8b3eef2073068)