Fix Problem with Memory By Role Panel on Main Grafana Dashboard (#425)

Author: Tim Middleton

dashboards/grafana/coherence-dashboard-main.json

@@ -1018,7 +1018,7 @@
       ],
       "targets": [
         {
-          "expr": "count(vendor_Coherence_Memory_HeapAfterGC_Max{cluster=~\"$ClusterName\"}) by (role)",
+          "expr": "avg(count(vendor_Coherence_Memory_HeapAfterGC_Max{cluster=~\"$ClusterName\"}) by (role, name)) by (role)",
           "format": "table",
           "instant": true,
           "interval": "",
@@ -2985,4 +2985,4 @@
     "list": []
   },
   "version": 1
-}
+}