Fixes a bug where user could not connect to devstack using the sdk example.

Added the ability to specify a service name when creating a service client.
Moved the default service name into the service definitions for both Identity and Storage
Modified the region resolution code to include a fall back when the given service name cannot be found
Updated unit tests and examples.

Closes-Bug: #1323260
Change-Id: Ifefd12ec783429f7a9c0f80c22bbd9aa6985df55
Merge "Fixes a bug where user could not connect to devstack using the sdk example."