And now pass the initial request to the backend...

I dislike this duplication of code from mod_proxy_http()
but maybe it's inevitable. I may create ap_proxy_create_headerb()
to create a header brigade that both modules can use.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1453574 13f79535-47bb-0310-9956-ffa450edef68