compositor: Don't just update uniforms when we change shaders
compositor: Don't just update uniforms when we change shaders

The uniforms change from surface to surface or output to output, so always
set them.

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