More gracefully fail when client goes off the rails.
More gracefully fail when client goes off the rails.

A client with certain URLs that go off the end of the valid world was
causing exceptions to be thrown not of the set of 'tame' errors.
Denote them as 404 since that is the nature of the failure.

michaelfardu/thinkconfluent,chenglch/confluent,xcat2/confluent,jjohnson42/confluent,jufm/confluent,jufm/confluent,jjohnson42/confluent,chenglch/confluent,whowutwut/confluent,michaelfardu/thinkconfluent,jufm/confluent,michaelfardu/thinkconfluent,whowutwut/confluent,chenglch/confluent,xcat2/confluent,jjohnson42/confluent,whowutwut/confluent,chenglch/confluent,jufm/confluent,michaelfardu/thinkconfluent,jjohnson42/confluent,jjohnson42/confluent,xcat2/confluent,xcat2/confluent,chenglch/confluent,whowutwut/confluent,jufm/confluent,xcat2/confluent,michaelfardu/thinkconfluent