Revert "Try to work around GDM custom.conf not existing"

This reverts commit 1b422dd.

This is no longer necessary (and apparently was never correct) since
as of ed62931 we properly write to
/etc.

build.sh

@@ -23,25 +23,7 @@ flatpak install --noninteractive --system im.riot.Riot com.nextcloud.desktopclie
 
 ### Configure system
 
-cat > /etc/gdm/custom.conf <<EOF
-# GDM configuration storage
-
-[daemon]
-AutomaticLoginEnable=true
-AutomaticLogin=seagloperator
-# Uncomment the line below to force the login screen to use Xorg
-#WaylandEnable=false
-
-[security]
-
-[xdmcp]
-
-[chooser]
-
-[debug]
-# Uncomment the line below to turn on debugging
-#Enable=true
-EOF
+sed -i 's/\[daemon\]/[daemon]\nAutomaticLoginEnable=true\nAutomaticLogin=seagloperator/' /etc/gdm/custom.conf
 systemctl enable seagl-reset-users.service
 
 cat > /etc/sudoers.d/10-unconditionally-grant-sudoers <<EOF