protocol: Add missing xml files to EXTRA_DIST
protocol: Add missing xml files to EXTRA_DIST

Reported by Sven Joachim <svenjoac@gmx.de>

krezovic/weston,kwm81/weston,xorgy/weston,Gnurou/weston,kwm81/weston,udoprog/weston,Tarnyko/weston-xdg_surface_present,udoprog/weston,mchalupa/weston,jonnylamb/weston,Fantu/compositor-spice,giucam/weston,sir-murray/weston,Gnurou/weston,xorgy/weston,krezovic/weston,Tarnyko/weston-xdg_surface_present,mchalupa/weston,eyolfson/weston,sir-murray/weston,Fantu/compositor-spice,Fantu/compositor-spice,eyolfson/weston,giucam/weston,jonnylamb/weston