[rest] Do not perform cache control when returning results

Review Request #1041 - Created Oct. 18, 2010 and submitted

Andrew Purtell
The REST interface currently provides MaxAge hints to HTTP cache servers when returning results, but does not do so in a way that makes much sense. For some other responses such as scanner results or schema, the REST interface provides a NoCache hint. That seems appropriate. Otherwise, especially given the rich configuration languages of caching servers such as Varnish, it is probably not appropriate to manage cache policy in the REST interface.