Subclass keystoneclient.session.Session to add the timing hooks to
record the elapsed time returned by requests.Response objects, including
the redirection history. Redirects are included individually and not
rolled into the total time for the original request.
This works for all clients that use OSC's session.
Closes-Bug: #1402577
Change-Id: I9360c90c151579b89a37edb8c11c17feb15b3cb9
