VOL-1470: Added explicit OMCI payload definition for inter-adapter messages

Change-Id: I82e779d5b559cf051907ac7e967ed42971a4d3e3
diff --git a/pyvoltha/protos/inter_container.proto b/pyvoltha/protos/inter_container.proto
index ac2af4f..acd3bc2 100644
--- a/pyvoltha/protos/inter_container.proto
+++ b/pyvoltha/protos/inter_container.proto
@@ -110,9 +110,16 @@
     int64 timestamp = 7;
 }
 
+message InterAdapterOmciMessage {
+    bytes message = 1; // OMCI_REQUEST or OMCI_RESPONSE
+}
+
 message InterAdapterResponseBody {
     bool status = 1;
-    google.protobuf.Any body = 2;
+    oneof payload {
+        google.protobuf.Any body = 2;
+        InterAdapterOmciMessage omci = 3; // OMCI_REQUEST or OMCI_RESPONSE
+    }
 }
 
 message InterAdapterMessage {