Fix HTTP hits metrics in dashboard

HTTP hits is emitted as _cumulative_ metrics by gerrit, so plotting the
sum of it meaningless as it just generates a linearly increasing trend
without actually showing how many HTTP hits are received.

Plot instead the _rate_ of the HTTP hits.

Change-Id: I92a701ff5ad7a63090bde96b1aa08501abb6d5c2
diff --git a/primary-replica/cf-dashboard.yml b/primary-replica/cf-dashboard.yml
index 8dbe49e..7f201a7 100644
--- a/primary-replica/cf-dashboard.yml
+++ b/primary-replica/cf-dashboard.yml
@@ -224,7 +224,7 @@
                             "height": 6,
                             "properties": {
                                 "metrics": [
-                                    [ { "expression": "m1+m2", "label": "HTTP hits per second", "id": "e2", "region": "${AWS::Region}" } ],
+                                    [ { "expression": "RATE(m1+m2)", "label": "HTTP hits per second", "id": "e2", "region": "${AWS::Region}" } ],
                                     [ "${MetricsCloudwatchNamespace}", "http/server/success_count_total", "InstanceId", "${PrimaryInstanceId}", "Type", "count", { "id": "m2", "visible": false } ],
                                     [ ".", "http/server/error_count_total", ".", ".", ".", ".", { "id": "m1", "visible": false } ]
                                 ],
diff --git a/single-primary/cf-service.yml b/single-primary/cf-service.yml
index 4592e27..90bb148 100644
--- a/single-primary/cf-service.yml
+++ b/single-primary/cf-service.yml
@@ -668,7 +668,7 @@
                             "height": 6,
                             "properties": {
                                 "metrics": [
-                                    [ { "expression": "m1+m2", "label": "HTTP hits per second", "id": "e2", "region": "${AWS::Region}" } ],
+                                    [ { "expression": "RATE(m1+m2)", "label": "HTTP hits per second", "id": "e2", "region": "${AWS::Region}" } ],
                                     [ "${MetricsCloudwatchNamespace}", "http/server/success_count_total", "InstanceId", "${InstanceId}", "Type", "count", { "id": "m2", "visible": false } ],
                                     [ ".", "http/server/error_count_total", ".", ".", ".", ".", { "id": "m1", "visible": false } ]
                                 ],