MINOR: stream/mux: implement websocket stream flag

Define a new stream flag SF_WEBSOCKET and a new cs flag CS_FL_WEBSOCKET.
The conn-stream flag is first set by h1/h2 muxes if the request is a
valid websocket upgrade. The flag is then converted to SF_WEBSOCKET on
the stream creation.

This will be useful to properly manage websocket streams in
connect_server().

(cherry picked from commit 90ac605ef35d60323cfe4bc26cd56c2f97dc2277)
[ad: remove non present flag from context]
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
5 files changed