[gnome-control-center] display: Unset primary from a turned off monitor

[Rui Matos <rtcm src gnome org>]

commit e1d5885ad4c62c0dd60ff5d0c48821e8c98cd1eb
Author: Rui Matos <tiagomatos gmail com>
Date:   Fri Apr 7 17:07:56 2017 +0200

    display: Unset primary from a turned off monitor
    
    When setting the primary monitor off we were setting all other
    monitors as non-primary which is clearly wrong. It only worked
    correctly because the backend code in GnomeRR would implicitly
    select a primary for us.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=782785

 panels/display/cc-display-panel.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/panels/display/cc-display-panel.c b/panels/display/cc-display-panel.c
index aaf23cc..2d91646 100644
--- a/panels/display/cc-display-panel.c
+++ b/panels/display/cc-display-panel.c
@@ -2354,6 +2354,7 @@ show_setup_dialog (CcDisplayPanel *panel)
               break;
 
             case DISPLAY_MODE_OFF:
+              primary = FALSE;
               clone = FALSE;
               active = FALSE;
               break;