The patch https://review.openstack.org/#/c/198506/ rename option
--os-endpoint-type to --os-interface a year ago, but lots of users
switch to osc from these project specified clients, like: novaclient
and neutronclient, they used OS_ENDPOINT_TYPE and --os-endpoint-type
for long time, we should add the notes into openstackclient manpage,
let them know the gap exists, and how to make it works.
Change-Id: Ic84a60744aa4e519994a18104deae0c2b5b8b0ed
Closes-Bug: #1678144