Re: Convert ConcatProxyServlet to use ConcatUriManager (issue224074)

[johnfargo]

Note: In addition to depending on the other referenced CL, this CL will
be updated to augment ConcatUriManager with
@ImplementedBy(DefaultConcatUriManager.class), and will include
container config updates.

http://codereview.appspot.com/224074/show