Added ap_sub_req_method_uri() for doing a subrequest with a method

other than GET, and const'd the definition of method in request_rec.

Submitted by:	Greg Stein <gstein@lyra.org>
Reviewed by:	Roy Fielding, Dean Gaudet, Doug MacEachern


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@82870 13f79535-47bb-0310-9956-ffa450edef68