Increase apache ServerLimit and workers to 100
Increase apache ServerLimit and workers to 100

Increase apache serverlimit and maxrequestworkers to 100
in low-memory-usage template.
We have been reaching the limit with all the OpenStack services that we run in WSGI.
Increasing the number will help us to promote packages in TripleO CI.

Change-Id: I3f71f279a8dfaee9db5f5d1091ad079d9170de1f

openstack/tripleo-heat-templates,dprince/tripleo-heat-templates,dprince/tripleo-heat-templates,openstack/tripleo-heat-templates