Install and configure NTP in undercloud/overcloud

This is especially important for the Overcloud at this
point because on real baremetal deployments clock skew
can often cause Neutron agents to fail to register
with the controller... thus making devtest_overcloud.sh
fail.

Change-Id: I6d19d9ce29a65c9bec01297cc335c9c39d061b4f
Closes-bug: #1309677
Merge "Install and configure NTP in undercloud/overcloud"