With the deprecation of python-keystoneclient the output of keystone
--version changed to:
DeprecationWarning: The keystone CLI is deprecated in favor of
python-openstackclient. For a Python library, continue using
python-keystoneclient. 'python-keystoneclient.', DeprecationWarning)
1.3.0
Because of that it is necessary to only handle the last line of the
output to extract the version string.
Change-Id: Ibdfaa1de4f1c8880ce1a049fec9bea3004c11fea
d1a9fc4f90