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 volumes_extensions_client use **kwargs. Partially implements blueprint consistent-service-method-names Change-Id: Ie7f61741d54a629a15b1e2b8fce178ebc06176d3