[gnome-flashback] backends: initialize current_mode variable

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 5e00c43dff14cb0c77498d39507e69176a377780
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Thu Oct 31 22:53:46 2019 +0200

    backends: initialize current_mode variable
    
    https://github.com/i3-gnome/i3-gnome/issues/49

 backends/gf-monitor.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/backends/gf-monitor.c b/backends/gf-monitor.c
index afbb20f..8bd7337 100644
--- a/backends/gf-monitor.c
+++ b/backends/gf-monitor.c
@@ -993,6 +993,7 @@ gf_monitor_derive_current_mode (GfMonitor *monitor)
   GList *l;
 
   priv = gf_monitor_get_instance_private (monitor);
+  current_mode = NULL;
 
   for (l = priv->modes; l; l = l->next)
     {