Updated openstack/openstack
Project: openstack/nova  2f1cc501c1e4eaa696543261b8f03590f663b220

initialize objects with context in cells

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: I5a7e3c1da6f9e2efaf296dd392e5ce9942c5729c