Fix ceph dashboard bug

Fix typo. 'Avg OSD Commit Latency' tab have to show commit latency and
be based on ceph_commit_latency metrics.
Change-Id: I8383400990bcf7e504b5f7e8391d04becb5f530c
diff --git a/ceph/files/grafana_dashboards/ceph_cluster_prometheus.json b/ceph/files/grafana_dashboards/ceph_cluster_prometheus.json
index 2bd96bd..a95759c 100644
--- a/ceph/files/grafana_dashboards/ceph_cluster_prometheus.json
+++ b/ceph/files/grafana_dashboards/ceph_cluster_prometheus.json
@@ -1247,7 +1247,7 @@
           "tableColumn": "Value",
           "targets": [
             {
-              "expr": "avg(ceph_commit_latency_sum) / avg(ceph_commitcycle_latency_avgcount)",
+              "expr": "avg(ceph_commit_latency_sum) / avg(ceph_commit_latency_avgcount)",
               "format": "time_series",
               "interval": "",
               "intervalFactor": 1,