Make live_migrate_server use **kwargs

As we discussed on
http://lists.openstack.org/pipermail/openstack-dev/2015-July/068864.html
All http POST/PUT methods need to contain **kwargs as their arguments.
This patch makes live_migrate_server use **kwargs.

Partially implements blueprint consistent-service-method-names

Change-Id: I4371de93c40176e92d605fed352743c6a3e04fd7
3 files changed