Fix inconsistency (nit)

Word choice of description for "host-evacuate-live" is slightly
different from that in novaclient ("migrate of" instead of "migrate off").
https://github.com/openstack/python-novaclient/blob/master/doc/source/cli/nova.rst#nova-host-evacuate-live
They are supposed to be exactly the same, so use "migrate off" to
keep consistent.

Change-Id: Ie54c6ed83b6e9a3116e1832b3fb36dd80781366d

Author: git861

doc/source/cli/data/nova.csv

@@ -45,7 +45,7 @@ get-vnc-console,console url show --novnc | --xvpvnc,Get a vnc console to a serve
 host-action,,Perform a power action on a host.
 host-describe,host show,Describe a specific host.
 host-evacuate,,Evacuate all instances from failed host.
-host-evacuate-live,,Live migrate all instances of the specified host to other available hosts.
+host-evacuate-live,,Live migrate all instances off the specified host to other available hosts.
 host-list,host list,List all hosts by service.
 host-meta,,Set or Delete metadata on all instances of a host.
 host-servers-migrate,,Cold migrate all instances off the specified host to other available hosts.