Fix the --min-prefix-length, --max-prefix-length and
--default-prefix-length options for the "os subnet pool create" and
"os subnet pool set" commands. Using these options caused the
commands to fail with "HttpException: Bad Request" because unrecognized
attributes were passed to the REST API.
No release note was added since these commands are new and haven't
been released.
Change-Id: I2f765750f79dc91d6c1f5962f699fbf2ee38657a
Closes-Bug: #1564004
9174bc0f02