QA: Remove logic for inexistant "wpvector-collapsiblenav" option

This option was never part of MediaWiki core and shouldn't have
been here in the first place.

It was removed from the Vector extension in October 2013 with I33dc0033c.

Not sure what this code is for or why it's not failing.

Change-Id: Ie552d9de3aa1f123a8f1c9414b444481461b4ec6
Merge "QA: Remove logic for inexistant "wpvector-collapsiblenav" option"