VOL-1156 Re-factor openolt driver

Allows re-use of common code among backends for multiple hardware
and simulators.

Change-Id: If5f0147d2eef7c1f9cbcda394d06a2070b4be275
diff --git a/src/indications.cc b/src/indications.cc
index 4d7a393..203b675 100644
--- a/src/indications.cc
+++ b/src/indications.cc
@@ -32,7 +32,7 @@
 
 using grpc::Status;
 
-Queue<openolt::Indication> oltIndQ;
+extern Queue<openolt::Indication> oltIndQ;
 //Queue<openolt::Indication*> oltIndQ;