Remove attributes that exist only because of copy&paste from keystone

The admin/regular/service user/password as well as the admin token
clearly come straight from the keystone barclamp but have no use here. I
guess this barclamp was initially created as a copy of the keystone
barclamp.
Merge pull request #49 from vuntz/no-keystone-copy

Remove attributes that exist only because of copy&paste from keystone