applicationserver: don't set beta's twemproxy to false

It's not accomplishing anything anyway, since mediawiki is included
elsehwere; twemproxy is in fact already provisioned on labs hosts.

Change-Id: Ieffec56b7328b5d52da4e043512bba296701d1d0
Merge "applicationserver: don't set beta's twemproxy to false" into production