reorder keybindings to show upstream defaults in gnome-control-center

We have some keybinding overrides that add <primary><super> alternatives to WM actions. These were apparently inherited from Unity.

in some cases the alternate keybinding is listed before the upstream default. Which causes the alternate keybinding to be displayed in gnome-control-center rather than the upstream one (which in all cases is simpler).

Until a decision is made as to if we need to keep these overrides atleast reorder them so the upstream keybindings are displayed in g-c-c.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: vanilla-gnome-default-settings 17.10.4
ProcVersionSignature: Ubuntu 4.15.0-20.21-generic 4.15.17
Uname: Linux 4.15.0-20-generic x86_64
ApportVersion: 2.20.9-0ubuntu7
Architecture: amd64
CurrentDesktop: GNOME
Date: Sun May 13 12:52:38 2018
InstallationDate: Installed on 2016-05-27 (715 days ago)
InstallationMedia: Ubuntu-GNOME 16.04 LTS "Xenial Xerus" - Release amd64 (20160509)
PackageArchitecture: all
SourcePackage: ubuntu-gnome-default-settings
UpgradeStatus: Upgraded to bionic on 2018-02-11 (91 days ago)