MINOR: stream-int: Handle appctx case first when releasing the endpoint

Stream-interfaces will be moved in the conn-stream and the appctx will be
moved at the same level than the muxes. Idea is to merge the
stream-interface and the conn-stream and have a better symmetry between the
muxes and the applets. To limit bugs during this refactoring, when the SI
endpoint is released, the appctx case is handled first.
diff --git a/include/haproxy/stream_interface.h b/include/haproxy/stream_interface.h
index 88c8101..c1c2b03 100644
--- a/include/haproxy/stream_interface.h
+++ b/include/haproxy/stream_interface.h
@@ -177,17 +177,17 @@
 	if (!si->end)
 		return;
 
-	if ((cs = objt_cs(si->end))) {
+	if ((appctx = objt_appctx(si->end))) {
+		if (appctx->applet->release && !si_state_in(si->state, SI_SB_DIS|SI_SB_CLO))
+			appctx->applet->release(appctx);
+		appctx_free(appctx);
+	}
+	else if ((cs = objt_cs(si->end))) {
 		if (si->wait_event.events != 0)
 			cs->conn->mux->unsubscribe(cs, si->wait_event.events,
 			    &si->wait_event);
 		cs_destroy(cs);
 	}
-	else if ((appctx = objt_appctx(si->end))) {
-		if (appctx->applet->release && !si_state_in(si->state, SI_SB_DIS|SI_SB_CLO))
-			appctx->applet->release(appctx);
-		appctx_free(appctx);
-	}
 	si_detach_endpoint(si);
 }