Remove blank values in namespaces array.

The inline template is using compact which is not removing
the blank values. A call to delete function from stdlib is
needed to remove the blank values.

Change-Id: I7cf3ca383572d569a7e89431dcc39385605cf820

manifests/agent/polling.pp

@@ -78,7 +78,7 @@ class ceilometer::agent::polling (
     }
   }
 
-  $namespaces = [$central_namespace_name, $compute_namespace_name, $ipmi_namespace_name]
+  $namespaces = delete([$central_namespace_name, $compute_namespace_name, $ipmi_namespace_name], '')
   $namespaces_real = inline_template('<%= @namespaces.select { |x| x and x !~ /^undef/ }.compact.join "," %>')
 
   package { 'ceilometer-polling':

releasenotes/notes/fix_polling_agent_namespaces-6a79b7e42601f950.yaml

@@ -0,0 +1,3 @@
+---
+issues:
+  - Delete blank values from ceilometer::agent::polling namespaces array.