[gnome-settings-daemon] color: Do not attempt to set the VCGT tables before start

[Richard Hughes <rhughes src gnome org>]

commit fa0ff6dc0e6eb7ce3e5982e0ccd6e23cdfe77c4d
Author: Richard Hughes <richard hughsie com>
Date:   Wed Feb 1 15:53:50 2017 +0000

    color: Do not attempt to set the VCGT tables before start

 plugins/color/gsd-color-state.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/plugins/color/gsd-color-state.c b/plugins/color/gsd-color-state.c
index 8bb9090..171c53a 100644
--- a/plugins/color/gsd-color-state.c
+++ b/plugins/color/gsd-color-state.c
@@ -1259,6 +1259,11 @@ gcm_session_set_gamma_for_all_devices (GsdColorState *state)
         GsdColorStatePrivate *priv = state->priv;
         guint i;
 
+        /* setting the temperature before we get the list of devices is fine,
+         * as we use the temperature in the calculation */
+        if (priv->state_screen == NULL)
+                return;
+
         /* get STATE outputs */
         outputs = gnome_rr_screen_list_outputs (priv->state_screen);
         if (outputs == NULL) {