Add Sahara plugins list as a configurable parameter

The hardcoded list should be configurable, and defaulted
to their current value.

Change-Id: I517aa61f21c6f4d0975b10a7aa85177c543487e0
Closes-bug: 1560098

puppet/services/sahara-base.yaml

@@ -44,6 +44,10 @@ parameters:
     type: string
     default: ''
     description: Set to True to enable debugging on all services.
+  SaharaPlugins:
+    default: ["ambari","cdh","mapr","vanilla","spark","storm"]
+    description: Sahara enabled plugin list
+    type: comma_delimited_list
 
 outputs:
   role_data:
@@ -69,13 +73,7 @@ outputs:
         sahara::auth_uri: {get_param: [EndpointMap, KeystoneInternal, uri] }
         sahara::identity_uri: { get_param: [EndpointMap, KeystoneAdmin, uri_no_suffix] }
         sahara::use_neutron: true
-        sahara::plugins:
-          - ambari
-          - cdh
-          - mapr
-          - vanilla
-          - spark
-          - storm
+        sahara::plugins: {get_param: SaharaPlugins}
         sahara::rpc_backend: rabbit
         sahara::admin_tenant_name: 'service'
         sahara::db::database_db_max_retries: -1