VOL-1623 Modified flow API towards adapter to contain addtional info needed to process the flow without sync call back to core

Commit depending on this : https://gerrit.opencord.org/#/c/14767/

Documented comments

Change-Id: Idad6ebb2ebaa42391b6d7be865e0bda9e74e7e07
diff --git a/protos/voltha_protos/voltha.proto b/protos/voltha_protos/voltha.proto
index a6f9ee0..75199aa 100644
--- a/protos/voltha_protos/voltha.proto
+++ b/protos/voltha_protos/voltha.proto
@@ -150,6 +150,12 @@
     string id = 2;
 }
 
+// Additional information required to process flow at device adapters
+message FlowMetadata {
+    // Meters associated with flow-update to adapter
+    repeated openflow_13.ofp_meter_config meters = 1;
+}
+
 /*
  * Voltha APIs
  *