monitoring: service monitor should not use mgr_role label

The service monitor selectors need to match the mgr service labels.
Since the mgr service labels don't use the mgr_role (only the mgr
service selectors use the mgr_role), the mgr_role should be removed
from the service monitor.

Signed-off-by: travisn <tnielsen@redhat.com>
(cherry picked from commit 754f073aa5)

deploy/examples/monitoring/service-monitor.yaml

@@ -11,10 +11,9 @@ spec:
       - rook-ceph
   selector:
     matchLabels:
-      mgr_role: active
       app: rook-ceph-mgr
       rook_cluster: rook-ceph
   endpoints:
-  - port: http-metrics
-    path: /metrics
-    interval: 5s
+    - port: http-metrics
+      path: /metrics
+      interval: 5s