Support ReceiveBufferSize. (Yes, I did test it.)

Reviewed By: Sameer Parekh, Brian Behlendorf
Submitted By: Phillip A. Prindeville


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@78844 13f79535-47bb-0310-9956-ffa450edef68