load mod_rewrite on terbium Apache

needed for rewrites such as in Ib48b514cf8080f7b3
or we are getting "Invalid command 'RewriteEngine'.."
and Apache config test fails

Change-Id: Ie82addf1f521b71f57b7ec5a38d3729eff835d9d
RT: 6862
Merge "load mod_rewrite on terbium Apache" into production