beta: Remove Apache::Conf['hhvm_catchall'] from mediawiki::web::beta_sites

role::beta::appserver includes both mediawiki::web and
mediawiki::web::beta_sites. mediawiki::web includes
mediawiki::web::modules which declares
Apache::Conf['hhvm_catchall'] since
Ie7c0dc64f7c6268af79b774e8653f5d4da1710d9.

Beta has had a local hack for this created by jeremyb on 2014-09-10 and
I just got around to tracking down the source of the conflict.

Change-Id: Ibed9bb8df9f1bfbf316720ea0ddc3a91939b32d0
Merge "beta: Remove Apache::Conf['hhvm_catchall'] from mediawiki::web::beta_sites" into production