[ONOS-7137] Interfaces Discovery through gNMI

Also, bumped version of gNMI proto as supported by PI

Change-Id: If2903b2dc483f545893daae77f993cc7dadee468
diff --git a/protocols/gnmi/stub/src/main/proto/COMMIT_ID b/protocols/gnmi/stub/src/main/proto/COMMIT_ID
index 0ac43f2..acf773d 100644
--- a/protocols/gnmi/stub/src/main/proto/COMMIT_ID
+++ b/protocols/gnmi/stub/src/main/proto/COMMIT_ID
@@ -1,2 +1,2 @@
 https://github.com/openconfig/gnmi/blob/master/proto/gnmi/gnmi.proto
-8a14ac0e9ed67e08988f9913243d89f398454824
+9c8d9e965b3e854107ea02c12ab11b70717456f2