Add to storage-aggregation.conf

+ Prevent loss of Gnocchi status metrics with xFileFactor=0.0
+ Aggregate using max rather than avg (default)

Change-Id: I6f25e6821531729f639fc738c5530c28f80ab40c

ansible/install/roles/graphite/files/storage-aggregation.conf

@@ -0,0 +1,12 @@
+[gnocchi_status]
+# Prevent lose of gnocchi_status metrics when:
+#  collectd plugin interval > smallest frequency:history
+# When xFilesFactor = 0.0 any single datapoint will be "aggregated"
+# for the next configured retention period in storage-schemas.conf
+#
+# Also aggregationMethod here is max since the maximum of these
+# metrics is most representative of behavior.
+#
+pattern = ^.*\.gnocchi_status\.
+xFilesFactor = 0.0
+aggregationMethod = max