expand wikicode in 'Cite_error_refs_without_references_category'

The English Wikipedia version of the message invokes a Scribunto
module, thus making noreferences.py fail with pywikibot.InvalidTitle
(because of the curly brackets in it) when called with no arguments:
https://travis-ci.org/wikimedia/pywikibot-core/jobs/31712965

Ideally, the 'amenableparser' argument should be passed to the
allmessages API, but APISite.mediawiki_messages() doesn't have this
feature yet.

Change-Id: I88b4beeec0bc64e2586a6165bf6ae9d70522db5d