Move per role Services defaults into environment file

For parameter merge strategies to work we need to merge multiple environment
files, which doesn't consider the defaults defined in the heat template.

Moving where we define these defaults will enable the merge strategies
applied when appending services to roles in environment files to work.

Change-Id: I1ef1ad685c8a15308d051665c576a98b277f2496
Closes-Bug: #1635409

overcloud-resource-registry-puppet.j2.yaml

@@ -213,3 +213,8 @@ resource_registry:
 parameter_defaults:
   EnablePackageInstall: false
   SoftwareConfigTransport: POLL_TEMP_URL
+
+{% for role in roles %}
+  # Parameters generated for {{role.name}} Role
+  {{role.name}}Services: {{role.ServicesDefault|default([])}}
+{% endfor %}

overcloud.j2.yaml

@@ -121,7 +121,6 @@ parameters:
                  resource_registry) which represent nested stacks
                  for each service that should get installed on the {{role.name}} role.
     type: comma_delimited_list
-    default: {{role.ServicesDefault|default([])}}
 
   {{role.name}}Count:
     description: Number of {{role.name}} nodes to deploy