Merge r1674632 from trunk:

mod_proxy_wstunnel: Bypass the handler while the connection is not
upgraded to WebSocket, so that other modules can possibly take over
the leading HTTP requests.

Submitted by: ylavic
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1674661 13f79535-47bb-0310-9956-ffa450edef68