MINOR: stream-int: split si_prepare_embedded into si_prepare_none and si_prepare_applet

si_prepare_embedded() was used both to attach an applet and to detach
anything from a stream interface. Split it into si_prepare_none() to
detach and si_prepare_applet() to attach an applet.

si->conn->target is now assigned from within these two functions instead
of their respective callers.
diff --git a/include/proto/stream_interface.h b/include/proto/stream_interface.h
index bb0c16d..516b11e 100644
--- a/include/proto/stream_interface.h
+++ b/include/proto/stream_interface.h
@@ -51,6 +51,13 @@
 	return si->conn->ctrl;
 }
 
+static inline void si_prepare_none(struct stream_interface *si)
+{
+	si->ops = &si_embedded_ops;
+	conn_prepare(si->conn, NULL, NULL, NULL, si);
+	si->conn->target = NULL;
+}
+
 static inline void si_prepare_conn(struct stream_interface *si, const struct protocol *ctrl, const struct xprt_ops *xprt)
 {
 	si->ops = &si_conn_ops;
@@ -63,10 +70,11 @@
 	conn_assign(si->conn, &si_conn_cb, ctrl, xprt, si);
 }
 
-static inline void si_prepare_embedded(struct stream_interface *si)
+static inline void si_prepare_applet(struct stream_interface *si, struct si_applet *applet)
 {
 	si->ops = &si_embedded_ops;
 	conn_prepare(si->conn, NULL, NULL, NULL, si);
+	si->conn->target = &applet->obj_type;
 }
 
 /* Sends a shutr to the connection using the data layer */
diff --git a/src/session.c b/src/session.c
index 90bf3de..0f626cd 100644
--- a/src/session.c
+++ b/src/session.c
@@ -469,8 +469,7 @@
 	s->si[1].conn_retries = 0;  /* used for logging too */
 	s->si[1].release   = NULL;
 	s->si[1].send_proxy_ofs = 0;
-	s->si[1].conn->target = NULL;
-	si_prepare_embedded(&s->si[1]);
+	si_prepare_none(&s->si[1]);
 	s->si[1].exp       = TICK_ETERNITY;
 	s->si[1].flags     = SI_FL_NONE;
 
diff --git a/src/stream_interface.c b/src/stream_interface.c
index a38f53a..7faf85f 100644
--- a/src/stream_interface.c
+++ b/src/stream_interface.c
@@ -358,8 +358,7 @@
 {
 	DPRINTF(stderr, "registering handler %p for si %p (was %p)\n", app, si, si->owner);
 
-	si_prepare_embedded(si);
-	si->conn->target = &app->obj_type;
+	si_prepare_applet(si, app);
 	si->release = app->release;
 	si->flags |= SI_FL_WAIT_DATA;
 	return si->owner;