Added support for pm configuration and reporting to ponsim.

Change-Id: I047627253f60beb624d38bde1e5da31adc42312e
diff --git a/ponsim/grpc_server.py b/ponsim/grpc_server.py
index 20b5dab..cea0cc4 100644
--- a/ponsim/grpc_server.py
+++ b/ponsim/grpc_server.py
@@ -53,6 +53,10 @@
             self.ponsim.onu_install_flows(request.port, request.flows)
         return Empty()
 
+    def GetStats(self, request, context):
+        return self.ponsim.get_stats()
+
+
 class GrpcServer(object):
 
     def __init__(self, port, ponsim):