Update client-env to use openstackclient commands

Updated the only instance of a keystoneclient command, to
check if the identity service is enabled.

Change-Id: If86f71c1610a79690d6c6a8eb423b6fa234372bb
Enable colors for Sahara log

Change-Id: If915be21a7090c93e0be4c1961058c155ed9ca2c
Merge "Enable colors for Sahara log"
Merge "Update client-env to use openstackclient commands"
Merge commit 'refs/changes/83/86083/1' of git://gold.eng.hq.xensource.com/git/github/openstack-dev/devstack into tmpbranch