Default to keystone v2 auth if auth_url is not
Default to keystone v2 auth if auth_url is not

specified in contrail keystone auth config file,
to make it backward compatible to pre 3.2.6 builds.

Change-Id: I49886e5403ee051cbe5200d3da0dc4184b507ffc
Closes-Bug: 1727005

rombie/contrail-controller,rombie/contrail-controller,rombie/contrail-controller,nischalsheth/contrail-controller,nischalsheth/contrail-controller,nischalsheth/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,rombie/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,rombie/contrail-controller,nischalsheth/contrail-controller,eonpatapon/contrail-controller,eonpatapon/contrail-controller,nischalsheth/contrail-controller,eonpatapon/contrail-controller,eonpatapon/contrail-controller,nischalsheth/contrail-controller,nischalsheth/contrail-controller,eonpatapon/contrail-controller,nischalsheth/contrail-controller