Previous this was set the zake, but that was revert to missing
dependencies issue and because zake is a test fixture and not somthing
to deploy.
This change configures the Cinder dlm with this one is zookeeper.
And it installs tooz and the extra dependencies needed for the
zookeeper driver.
To do it, this commit have to introduce a new method for package
installation: 'pip_install_gr_extras package extra1,extra2'.
Change-Id: Idca310c08e345db59840eb31434c6cb1f849fa70
52b1074615