Prompt for auth options
Prompt for auth options

This is tolerant of os-client-config releases above 1.18.0 and will
start prompting for passwords when 1.21.0 or newer is present.

Once o-c-c 1.21.0 reaches the minimum in global requirements.txt
all of this hackery can go away.

Change-Id: I8054cc2372299592c4ecf9e7eb0e7971be51682b

dtroyer/osc-lib