Set the NTP server on Sahara too

Add a new parameter to the base sahara "service" which matches the name
of the parameter already used by the ntp service template.

The default_ntp_server option from sahara.conf only accepts one item
instead of an array, but it looks like get_param does the right thing
and feeds the option with the first value.
While the behavior of default_ntp_server may be improved,
this change should be good on the TripleO side now (and even
later, should default_ntp_server start accepting more values.)

Closes-Bug: #1638677
Change-Id: I1ffcc39b8bd762ad941bb7b3dca967b4d70e796d

deployment/sahara/sahara-base.yaml

@@ -52,6 +52,12 @@ parameters:
     type: string
     default: 'messagingv2'
     description: Driver or drivers to handle sending notifications.
+  NtpServer:
+    default: ['0.pool.ntp.org', '1.pool.ntp.org', '2.pool.ntp.org', '3.pool.ntp.org']
+    description: NTP servers list. Defaulted to a set of pool.ntp.org servers
+                 in order to have a sane default for Pacemaker deployments when
+                 not configuring this parameter by default.
+    type: comma_delimited_list
   RpcPort:
     default: 5672
     description: The network port for messaging backend
@@ -103,6 +109,7 @@ outputs:
           - {get_param: SaharaDebug }
         # Remove admin_password when https://review.openstack.org/442619 is merged.
         sahara::admin_password: {get_param: SaharaPassword}
+        sahara::default_ntp_server: {get_param: NtpServer}
         sahara::use_neutron: true
         sahara::plugins: {get_param: SaharaPlugins}
         sahara::rpc_backend: rabbit