[fractal/fractal-next] room: Fix set_predecessor()

[Julian Sparber <jsparber src gnome org>]

commit e0ffdf6d5bb171dfa2fa3380fc9c25fe9b82976e
Author: Julian Sparber <julian sparber net>
Date:   Sat Jan 15 14:40:39 2022 +0100

    room: Fix set_predecessor()

 src/session/room/mod.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/session/room/mod.rs b/src/session/room/mod.rs
index fd8c0f7b..87532a00 100644
--- a/src/session/room/mod.rs
+++ b/src/session/room/mod.rs
@@ -1037,7 +1037,7 @@ impl Room {
     fn load_predecessor(&self) -> Option<()> {
         let priv_ = imp::Room::from_instance(self);
 
-        if priv_.successor.get().is_some() {
+        if priv_.predecessor.get().is_some() {
             return None;
         }