[gimp] app: don't leak UI manager in GimpToolPath

[Ell <ell src gnome org>]

commit 10f9ee63c6c6d95d47790cf91ce56fc6e84835ac
Author: Ell <ell_se yahoo com>
Date:   Tue May 26 11:10:27 2020 +0300

    app: don't leak UI manager in GimpToolPath

 app/display/gimptoolpath.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
---
diff --git a/app/display/gimptoolpath.c b/app/display/gimptoolpath.c
index 2a1681d92e..ce99e2ad8c 100644
--- a/app/display/gimptoolpath.c
+++ b/app/display/gimptoolpath.c
@@ -318,10 +318,13 @@ gimp_tool_path_constructed (GObject *object)
 static void
 gimp_tool_path_dispose (GObject *object)
 {
-  GimpToolPath *path = GIMP_TOOL_PATH (object);
+  GimpToolPath        *path    = GIMP_TOOL_PATH (object);
+  GimpToolPathPrivate *private = path->private;
 
   gimp_tool_path_set_vectors (path, NULL);
 
+  g_clear_object (&private->ui_manager);
+
   G_OBJECT_CLASS (parent_class)->dispose (object);
 }