Fix to ensure endpoint_type is used by make_client()

This will fix an issue where neutronclient is ignoring the endpoint_type
passed to the client for v2 auth.

* make_client for '2.0' will now pass on the endpoint_type variable

Change-Id: I917ebee51254bc3e144f09573fa628d4ca192d13
Closes-Bug: #1368676
Merge "Fix to ensure endpoint_type is used by make_client()"