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/adapters/interface.py b/voltha/adapters/interface.py
index c7016d1..9aef84f 100644
--- a/voltha/adapters/interface.py
+++ b/voltha/adapters/interface.py
@@ -150,6 +150,13 @@
         :return:
         """
 
+    #def update_pm_collection(device, pm_collection_config):
+        """
+        Called every time a request is made to change pm collection behavior
+        :param device: A Voltha.Device object
+        :param pm_collection_config: A Pms
+        """
+
     def send_proxied_message(proxy_address, msg):
         """
         Forward a msg to a child device of device, addressed by the given