Fix a few issues with 'usage list'
Fix a few issues with 'usage list'

* Added number of servers column, was missing
* Added a new line character after the initial usage message

Change-Id: I6c4e5bda6ba9ceafa92ecf13987c56d0bbe99961

redhat-openstack/python-openstackclient,dtroyer/python-openstackclient,BjoernT/python-openstackclient,redhat-openstack/python-openstackclient,openstack/python-openstackclient,openstack/python-openstackclient,BjoernT/python-openstackclient,dtroyer/python-openstackclient