[gnome-settings-daemon/benzea/misc-fixes-2] power: Fix critical warning in CI job

[Benjamin Berg <bberg src gnome org>]

commit 9c7574080fb463513aa2c9b2302bb3c9daa1bb14
Author: Benjamin Berg <bberg redhat com>
Date:   Mon May 25 17:28:40 2020 +0200

    power: Fix critical warning in CI job
    
    We don't have a connector for the monitor in CI. Prevent the NULL string
    from reaching the StepUp/StepDown return value.

 plugins/power/gsd-power-manager.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
---
diff --git a/plugins/power/gsd-power-manager.c b/plugins/power/gsd-power-manager.c
index c7a16e8d..6e1e5ee9 100644
--- a/plugins/power/gsd-power-manager.c
+++ b/plugins/power/gsd-power-manager.c
@@ -2776,6 +2776,7 @@ backlight_brightness_step_cb (GObject *object,
         GDBusMethodInvocation *invocation = G_DBUS_METHOD_INVOCATION (user_data);
         GsdPowerManager *manager;
         GError *error = NULL;
+        const char *connector;
         gint brightness;
 
         manager = g_object_get_data (G_OBJECT (invocation), "gsd-power-manager");
@@ -2789,10 +2790,12 @@ backlight_brightness_step_cb (GObject *object,
                 g_dbus_method_invocation_take_error (invocation,
                                                      error);
         } else {
+                connector = gsd_backlight_get_connector (backlight);
+
                 g_dbus_method_invocation_return_value (invocation,
                                                        g_variant_new ("(is)",
                                                                       brightness,
-                                                                      gsd_backlight_get_connector 
(backlight)));
+                                                                      connector ? connector : ""));
         }
 }