Live migration fails using "openstack server migrate"

Description
===========

Attempting to migrate a server using the "openstack server migrate" command fails if the server lives on shared storage (like Ceph).

The problem is that nova/compute/api.py:live_migrate() expects a "block_migration" boolean whereas openstackclient/compute/v2/server.py:take_action() passes a "shared_migration" boolean.

Steps to reproduce
==================

Ensure instance in on shared storage and attempt to migrate it:

[root@phsospc2n2 ~]# openstack server migrate --live phsospc2n5 --shared-migration --wait testlm

Expected result
===============

[root@phsospc2n2 ~]# openstack server migrate --live phsospc2n5 --shared-migration --wait testlm
Complete

Actual result
=============

[root@phsospc2n2 ~]# openstack server migrate --live phsospc2n5 --shared-migration --wait testlm
phsospc2n4 is not on local storage: Block migration can not be used with shared storage. (HTTP 400) (Request-ID: req-7d535333-4220-457b-af81-0b90290bf84d)

Environment
===========

python-openstackclient-2.2.0-1.el7.noarch