mod_proxy_http2: not forwarding any 1xx responses on frontend HTTP/1.x...

mod_proxy_http2: not forwarding any 1xx responses on frontend HTTP/1.x connections. Unless its 100 and the client is expecting that.



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1770998 13f79535-47bb-0310-9956-ffa450edef68