config: fails to create tarball as xorg-server.conf file removed

Just need to update EXTRA_DIST

Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Gaetan Nadon <memsize@videotron.ca>
Signed-off-by: Keith Packard <keithp@keithp.com>
DIST_SUBDIRS needs to include glamor, even if it isn't built

Otherwise, glamor won't get cleaned for 'make distclean'

Signed-off-by: Keith Packard <keithp@keithp.com>