revise DISPOSE_PREVIOUS, again
revise DISPOSE_PREVIOUS, again

Perhaps it now works :(

See https://github.com/libvips/libvips/issues/1649

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