Make use of openstack.common.jsonutils.
Make use of openstack.common.jsonutils.

This patch imports jsonutils from openstack-common.  It removes the
equivalent code from nova.utils and then converts the code base to use
jsonutils.  The primary motivator for this change was to remove the rest
of the dependencies from nova.rpc on nova.utils.

Change-Id: If43658b9b098ed56cba018c81be268b8c3e2916a

citrix-openstack-build/oslo.versionedobjects,openstack/oslo.versionedobjects