Rewrite how proxy sends its request to allow input bodies to morph the request

bodies.  Previously, if an input filter changed the request body, the
original C-L would be sent which would be incorrect.

Due to HTTP compliance, we must either send the body T-E: chunked or include
a C-L for the request body.  Connection: Close is not an option.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@97812 13f79535-47bb-0310-9956-ffa450edef68