Make v2 create_user_ec2_credentials  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 create_user_ec2_credentials of v2 identity_client use **kwargs.

Partially implements blueprint consistent-service-method-names

Change-Id: I84b62041ee5e3811e9651ece2323b1f52065ff91
3 files changed