Updated openstack/openstack
Project: openstack/nova  ecf8916750b11fee3549e8b594a929461c786e0a

initialize objects with context in server groups api

These changes aim to clean up the pattern of passing a context in
object member functions create/destroy/refresh/save and instead
initialize the object with the context when it's constructed.

Related to blueprint kilo-objects

Change-Id: Ieb405b5cf8de40024a175771fba2f4c296af9e78