restore integration.mediawiki.org config

integration.mediawiki.org is supposed to redirect permanently to wm.org
equivalent.  When doing the documentation, we disabled its configuration
entirely and thus the redirection is not enabled.

This change reenable int.mw.org apache config (which just redirect).

Change-Id: I601b8b279d6e16331c76d802987a12beff89aea0