Use openstack-common's update.py script to pull in some recent changes:
* Add the Mapping interface to cfg.ConfigOpts
* Add support to cfg for disabling interspersed args
Make use of both of these in nova/flags.py.
Add some dire warnings to HACKING about directly modifying the copy of
openstack-common code. I'm confident they won't be ignored :-)
Change-Id: I7ef75d18922c0bbb8844453b48cad0418034bc11
67307bb7fe