[gnome-settings-daemon] common: Fix touchscreen vs display orientation mismatch under gdm

[Rui Matos <rtcm src gnome org>]

commit cf5b5fbab3c5a4d4a6385eae13d86d208a04d9d6
Author: Hans de Goede <hdegoede redhat com>
Date:   Fri Sep 29 16:56:10 2017 +0200

    common: Fix touchscreen vs display orientation mismatch under gdm
    
    We need to have gsd-wacom active under gdm so that when the LCD panel
    gets rotated the input coordinates from the touchscreen get adjusted
    accordingly.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=787884

 plugins/common/daemon-skeleton-gtk.h |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/plugins/common/daemon-skeleton-gtk.h b/plugins/common/daemon-skeleton-gtk.h
index 936c5b8..27aade6 100644
--- a/plugins/common/daemon-skeleton-gtk.h
+++ b/plugins/common/daemon-skeleton-gtk.h
@@ -49,7 +49,8 @@ static const char *gdm_helpers[] = {
        "power",
        "smartcard",
        "sound",
-       "xsettings"
+       "xsettings",
+       "wacom",
 };
 
 static gboolean