Initial commit for the PM management apis and placeholders for
implementation
Amendment: Made changes recommended by reviewers with the actual
changes this time.

Change-Id: I9a0d98d456f95a0eee67614f0bec43923815537b
diff --git a/voltha/core/adapter_agent.py b/voltha/core/adapter_agent.py
index 4859d27..7ba382b 100644
--- a/voltha/core/adapter_agent.py
+++ b/voltha/core/adapter_agent.py
@@ -34,10 +34,13 @@
 from voltha.protos.device_pb2 import Device, Port
 from voltha.protos.events_pb2 import KpiEvent, AlarmEvent, AlarmEventType, \
     AlarmEventSeverity, AlarmEventState, AlarmEventCategory
+from voltha.protos.device_pb2 import Device, Port, PmConfigs
+from voltha.protos.events_pb2 import KpiEvent
 from voltha.protos.voltha_pb2 import DeviceGroup, LogicalDevice, \
     LogicalPort, AdminState, OperStatus
 from voltha.registry import registry
 from voltha.core.flow_decomposer import OUTPUT
+import sys
 
 
 @implementer(IAdapterAgent)
@@ -177,6 +180,10 @@
         return self.update_flows_incrementally(
             device, flow_changes, group_changes)
 
+    #def update_pm_collection(self, device, pm_collection_config):
+    #    return self.adapter.update_pm_collection(device, pm_collection_config)
+
+
     # ~~~~~~~~~~~~~~~~~~~ Adapter-Facing Service ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
     def get_device(self, device_id):