Remove old driver mapping deprecation

This deprecation was introduced back in Grizzly, which will be EOL after
IceHouse. Removing to clean things up.

Change-Id: I509bb4115c3c88a7af7326125feb760f20847b8d
Merge "Remove old driver mapping deprecation"
(Test commit) Change README to reflect Jio's fork of Cinder

Change-Id: I3f26c0a736e63725aec24ca2fa12c707b8e6460f