Backport part of r216156;

  send_request_body makes it very difficult to follow all the mistakes
  in this code.  Fold send_request_body into ap_proxy_http_request
  so that proxy_http_request makes all of the elections.



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/proxy-reqbody-2.0.x@230709 13f79535-47bb-0310-9956-ffa450edef68