[amtk] utils: fix compilation warning with g_clear_pointer()

[Sébastien Wilmet <swilmet src gnome org>]

commit 0598aac3e5a25bd689cdecade58251d250ac1b45
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Fri Sep 6 16:48:32 2019 +0200

    utils: fix compilation warning with g_clear_pointer()
    
    The warning was:
    
    amtk-utils.c: In function ‘amtk_utils_bind_g_action_to_gtk_action’:
    amtk-utils.c:359:34: warning: function called through a non-compatible type
      359 |  g_clear_pointer (&target_value, (GDestroyNotify)g_variant_unref);
    /usr/include/glib-2.0/glib/gmem.h:121:8: note: in definition of macro ‘g_clear_pointer’
      121 |       (destroy) (_ptr);                                                        \
          |        ^~~~~~~
    
    Setting target_value to NULL afterwards is not needed because it's the
    end of the function.

 amtk/amtk-utils.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
---
diff --git a/amtk/amtk-utils.c b/amtk/amtk-utils.c
index 61e2f4d..a6e8fad 100644
--- a/amtk/amtk-utils.c
+++ b/amtk/amtk-utils.c
@@ -356,7 +356,11 @@ amtk_utils_bind_g_action_to_gtk_action (GActionMap     *g_action_map,
 
 out:
        g_free (g_action_name);
-       g_clear_pointer (&target_value, (GDestroyNotify)g_variant_unref);
+
+       if (target_value != NULL)
+       {
+               g_variant_unref (target_value);
+       }
 }
 
 /**