The *_swift_info functions use in module global dicts to provide a
registry mechanism for registering and getting swift info.
This is an abnormal pattern and doesn't quite fit into utils. Further
we looking at following this pattern for sensitive info to trim in the
future.
So this patch does some house cleaning and moves this registry to a new
module swift.common.registry. And updates all the references to it.
For backwards compat we still import the *_swift_info methods into utils
for any 3rd party tools or middleware.
Change-Id: I71fd7f50d1aafc001d6905438f42de4e58af8421
589ac355f3