Fix obscure double url bug in container quota middleware

With the container quota middleware on, if you made a request similar to the
following one you'd get a 500 response.

curl -i -X PUT -H 'X-Auth-Token: token'
http://127.0.0.1:8080/v1/AUTH_testhttp://something/something_else

(Note the double url.)

This was due to a mismatch in how split_path() was called in the middleware and
in the get_container_info().

This change fixes that mismatch and the bug.

Change-Id: Ie42ab585b942b7201e13b02a0c706532952aac60
Merge "Fix obscure double url bug in container quota middleware"