Add admin role back to ceilometer service user

admin is required for the discovery process in the polling agents.

Change-Id: I255184c544c6cc43c832d7c5d19d09b9f43adb10
Closes-Bug: 1422488
diff --git a/lib/ceilometer b/lib/ceilometer
index 698e8b0..c449ad2 100644
--- a/lib/ceilometer
+++ b/lib/ceilometer
@@ -108,7 +108,7 @@
     # Ceilometer
     if [[ "$ENABLED_SERVICES" =~ "ceilometer-api" ]]; then
 
-        create_service_user "ceilometer"
+        create_service_user "ceilometer" "admin"
 
         if [[ "$KEYSTONE_CATALOG_BACKEND" = 'sql' ]]; then
             local ceilometer_service=$(get_or_create_service "ceilometer" \