MINOR: stream-int: add a new pointer to the end point

The end point will correspond to either an applet context or a connection,
depending on the object type. For now the pointer remains null.
diff --git a/include/proto/stream_interface.h b/include/proto/stream_interface.h
index 516b11e..6dffcaf 100644
--- a/include/proto/stream_interface.h
+++ b/include/proto/stream_interface.h
@@ -54,6 +54,7 @@
 static inline void si_prepare_none(struct stream_interface *si)
 {
 	si->ops = &si_embedded_ops;
+	si->end = NULL;
 	conn_prepare(si->conn, NULL, NULL, NULL, si);
 	si->conn->target = NULL;
 }
@@ -61,18 +62,21 @@
 static inline void si_prepare_conn(struct stream_interface *si, const struct protocol *ctrl, const struct xprt_ops *xprt)
 {
 	si->ops = &si_conn_ops;
+	si->end = NULL;
 	conn_prepare(si->conn, &si_conn_cb, ctrl, xprt, si);
 }
 
 static inline void si_takeover_conn(struct stream_interface *si, const struct protocol *ctrl, const struct xprt_ops *xprt)
 {
 	si->ops = &si_conn_ops;
+	si->end = NULL;
 	conn_assign(si->conn, &si_conn_cb, ctrl, xprt, si);
 }
 
 static inline void si_prepare_applet(struct stream_interface *si, struct si_applet *applet)
 {
 	si->ops = &si_embedded_ops;
+	si->end = NULL;
 	conn_prepare(si->conn, NULL, NULL, NULL, si);
 	si->conn->target = &applet->obj_type;
 }
diff --git a/include/types/stream_interface.h b/include/types/stream_interface.h
index b7f1a5a..fc09aa6 100644
--- a/include/types/stream_interface.h
+++ b/include/types/stream_interface.h
@@ -160,6 +160,7 @@
 	unsigned int exp;       /* wake up time for connect, queue, turn-around, ... */
 	void *owner;            /* generally a (struct task*) */
 	unsigned int err_type;  /* first error detected, one of SI_ET_* */
+	enum obj_type *end;     /* points to the end point (connection or appctx) */
 
 	struct connection *conn; /* descriptor for a connection */
 	struct si_ops *ops;     /* general operations at the stream interface layer */
diff --git a/src/stream_interface.c b/src/stream_interface.c
index 7faf85f..55342e7 100644
--- a/src/stream_interface.c
+++ b/src/stream_interface.c
@@ -372,6 +372,7 @@
 	si->release = NULL;
 	si->owner = NULL;
 	si->conn->target = NULL;
+	si->end = NULL;
 }
 
 /* This callback is used to send a valid PROXY protocol line to a socket being