BUG/MEDIUM: connection/mux: take care of serverless proxies

Commit 7ce0c89 ("MEDIUM: mux: Use the mux protocol specified on
bind/server lines") assumed a bit too strongly that we could only have
servers on the connect side :-) It segfaults under this config :

    defaults
        contimeout      5s
        clitimeout      5s
        srvtimeout      5s
        mode http

    listen test1
        bind :8001
        dispatch 127.0.0.1:8002

    frontend test2
        mode http
        bind :8002
        redirect location /

No backport needed.
1 file changed