Update --max-width help
Update --max-width help

The --max-width help said that 0 would disable, when in fact any value
less than 1 would disable. Updated the help to match the behavior.

Change-Id: I36066fb4b54ec857d381ada200fce3fb42d8236c
Closes-Bug: #1564433

dtroyer/cliff,openstack/cliff,openstack/cliff,dtroyer/cliff