Set up Apache on build server for HA

In HA scenarios the build server needs apache::default_vhost enabled but
the other Apache nodes in HA do not.

Change-Id: If891c6895ee53f7f24de8c1b0c3f0bae3c53c5da
Closes-Bug: #1324593
(cherry picked from commit 585834da2353b2649b190d40fad42137063cd03a)