Fix Quota rest rate limiter support

This fixes an issue where the url has a canonical url (eg /r/).

The fix is to change getRequestURI to getServletPath.

The difference between both those functions is the fact that
getRequestURI returns /r/ and getServletPath does not.

Bug: Issue 10644
Change-Id: I8f305d3c2797eeea31cb86df1ac0eb1d4dfaddba