Update new driver review checklist
Update new driver review checklist

- add info about reporting common config options
- update python version testing info for third party CI
- add info about unit test discovery
- add warning about a child driver reporting parent capabilities
  that it may not have

Change-Id: Ife214328cdb08ea9a3939b61469fd70b100ed3c7

mahak/cinder,openstack/cinder,mahak/cinder,openstack/cinder