Adjust sample config for keystoneclient 0.8.0 release

Helps fixing the gate again.

Change-Id: Ic962613fd7ee3e978890c25f911f509e9533ef8a
(cherry picked from commit da2dbd35de752d4dd47859c8b9197b00c53dd872)
Opening stable/icehouse

Bump version to next stable release on icehouse branch, and set
defaultbranch in .gitreview for convenience.

Change-Id: I8eae47f57ad05f0047eb10f0ec087044fa1fd340