MAJOR: stream_int: use a common stream_int_shut*() functions regardless of the data layer

Up to now, we had to use a shutr/shutw interface per data layer, which
basically means 3 distinct functions when we include SSL :
  - generic stream_interface
  - sock_raw
  - sock_ssl

With this change, the code located in the stream_interface manages all the
stream_interface and buffer updates, and calls the data layer hooks when
needed.

At the moment, the socket layer hook had been implicitly considered as
being a regular socket, so the si_shut*() functions call the normal
shutdown() and EV_FD_CLR() functions on the fd if a socket layer is
defined. This may change in the future. The stream_int_shut*()
functions don't call EV_FD_CLR() so that they can later be embedded
in lower layers.

Thus, the si->data->shutr() is not called anymore and si->data->shutw()
is called to close the data layer only (eg: only for SSL).

Proceeding like this is very important because it's the only way to be
able not to rely on these functions when called from the connection
handlers, and call the data layers' instead.
diff --git a/include/types/stream_interface.h b/include/types/stream_interface.h
index 851870f..20787e8 100644
--- a/include/types/stream_interface.h
+++ b/include/types/stream_interface.h
@@ -110,8 +110,8 @@
 
 struct sock_ops {
 	void (*update)(struct stream_interface *);  /* I/O update function */
-	void (*shutr)(struct stream_interface *);   /* shutr function */
-	void (*shutw)(struct stream_interface *);   /* shutw function */
+	void (*shutr)(struct connection *, int);    /* shutr function */
+	void (*shutw)(struct connection *, int);    /* shutw function */
 	void (*chk_rcv)(struct stream_interface *); /* chk_rcv function */
 	void (*chk_snd)(struct stream_interface *); /* chk_snd function */
 	int (*read)(struct connection *conn);       /* read callback after poll() */