Give flatpak builds access to the dri device

This prevents the following warning:
 * libEGL warning: wayland-egl: could not open /dev/dri/card0

Make flatpak finish-args configurable and allow overriding the
defaults entirely.

Change-Id: If777eb5d31da4bca9cef276d7c8aaeae76f12211
Signed-off-by: Mat Booth <mat.booth@redhat.com>
2 files changed