2.25.0 milestone for liberty series

Release 2.24.1

Fixes Bug:
 - 1437244 - FloatingIP has wrong __repr__

python-novaclient 2.24.0 release

Release 2.23.0 with bug fixes.

python-novaclient 2.22.0 release

Release 2.21.0

Release with final Juno requirements

Pre-juno release.

Fix critical issue in 2.18.0 related to changed client exceptions.

Release as requested on openstack-dev. Fixes released include resolvi…

…ng bug 1297796, which relates to process safety.