Migrate json to glance.openstack.common.jsonutils

Every call to json.loads/json.dumps have been changed to
jsonutils.loads/jsonutils.dumps respectively. Import json has been removed
also replaced by import glance.openstack.common.jsonutils

654d80b416dc5f413cb791aa838ec8688bf7da44 Create openstack.common.jsonutils

Change-Id: I8ef580e5eb91526dfaef37050ce1f5c6d88d56b5
Closes-bug: #1257922
Merge "Migrate json to glance.openstack.common.jsonutils"