remove missing res warning for tiff
remove missing res warning for tiff

remove the warning for no res info in tiff, it happened all the time and
wasn't important

jcupitt/libvips,lovell/libvips,lovell/libvips,lovell/libvips,jcupitt/libvips,lovell/libvips,jcupitt/libvips,jcupitt/libvips