[V3] Make service_client 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 service_client use **kwargs.

Partially implements blueprint consistent-service-method-names

Change-Id: I02242ad94989ae234963014aa58ffe7b3787018d
4 files changed