Enable haproxy statistics unix socket

Enable haproxy statistics unix socket

By enabling the statistics socket we allow the collection
of statistics over time for haproxy.

This socket is set to "user" level, so this socket is limited
to read-only. The "stats timeout" line is optional, but since the
default timeout of the stats socket is 10s, we set this higher.

Change-Id: I22d3ab771e981be0d2c74b60443d276973bc1639