Git: Specify shotcurts in StashDialog

Change-Id: I05eabdd146f66a908e0cf44f229a0a2e6efe4f93
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>