Update the Neutron CLI decoder document
Update the Neutron CLI decoder document

The floatingip-disassociate mapping had 'port' instead of
'--port', also fixed a few places where 'unset' was missing
from some of the mappings.

Trivialfix

Change-Id: I3b01db28dda674e9988176d496154fbd26e4449f

openstack/python-openstackclient,dtroyer/python-openstackclient,openstack/python-openstackclient,dtroyer/python-openstackclient