don't add wl evas callbacks multiple times
don't add wl evas callbacks multiple times

 #sigh

tizenorg/platform.upstream.enlightenment,FlorentRevest/Enlightenment,tasn/enlightenment,tasn/enlightenment,FlorentRevest/Enlightenment,tasn/enlightenment,FlorentRevest/Enlightenment,rvandegrift/e,tizenorg/platform.upstream.enlightenment,rvandegrift/e,tizenorg/platform.upstream.enlightenment,rvandegrift/e