Improve code suffering from PHP 5.3's lack of support for foo()[]

Improve code suffering from PHP 5.3's lack of support for foo()[]

I searched for /\$(\S+) = (.+?\(.*?\);)\n.*?\$\1\[/, ignored
everything involving isset(), unset() or array assigments, then
skimmed through the remaining results and changed things where they
made sense. These changes were not automated, so please review them.

Change-Id: Ib37b4c66fc57648470f151ad412210b3629c2538