Notifier Proxy

Proxy for making notification calls in manner safe for conversion to
oslo.messaging.

Change-Id: I046f0f5383ecec7d95e1a253d5abc125350fed95
Fix a bug in safe_encode where it returns a bytes object in py3

Used the six module to dynamically determine python version
and decode the returned bytes object to a string if python3 is
being used

Change-Id: I9e46199e86cba63f530eaef47e53f0de170bdd94
Closes-Bug: #1249995
Merge "Notifier Proxy"
Merge "Fix a bug in safe_encode where it returns a bytes object in py3"