[VOL-4371]  Voltha protos cleanup

Details can be found at:
https://docs.google.com/document/d/1UzfuiPzxYYTULyERk8nKfgzW9QAnwEdtfw_J4UoFyYo/edit

Change-Id: Iad2efddf306234e282af5d518fd435a6b50b1c41
diff --git a/protos/voltha_protos/openolt.proto b/protos/voltha_protos/openolt.proto
index b68727a..03fe064 100755
--- a/protos/voltha_protos/openolt.proto
+++ b/protos/voltha_protos/openolt.proto
@@ -20,9 +20,9 @@
 
 package openolt;
 import "google/api/annotations.proto";
-import public "voltha_protos/tech_profile.proto";
-import public "voltha_protos/common.proto";
+import "voltha_protos/tech_profile.proto";
 import "voltha_protos/ext_config.proto";
+import "voltha_protos/extensions.proto";
 
 service Openolt {
 
@@ -196,7 +196,7 @@
         };
     }
 
-    rpc GetExtValue(ValueParam) returns (common.ReturnValues) {
+    rpc GetExtValue(ValueParam) returns (extension.ReturnValues) {
         option (google.api.http) = {
           post: "/v1/GetExtValue"
           body: "*"
@@ -750,7 +750,7 @@
 
 message ValueParam {
 	Onu onu = 1;
-	common.ValueType.Type value = 2;
+	extension.ValueType.Type value = 2;
 }
 
 message PonRxPowerData {