Do not ignore NtpServer by default
Do not ignore NtpServer by default

Before we had the NtpPool option which has been added because of chrony,
the NtpServer parameter was the way to configure the ntp sources for
TripleO. We should not ignore them because this can break people coming
from previous versions.

Change-Id: I09c08740a3bd9b64950430496fecdae903bb6ebc
Closes-Bug: #1802538

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