This fixes the case that when a request looking like
http://example.com/resource/volume
and containing a token comes to the proxy, we translate it to
http://cinder.local/volume/<project_id>
This happens because we populate the project_id information of
a request either from the url, or from the token.
Change-Id: Ie83fec4910eff750ba15f5485428c23ec3505e3b