resolve flup dependency
openwrt dropped this package, see https://git.openwrt.org/?p=feed/packages.git;a=commit;h=33525fa8d5dd0b878329971fb78c6a623207dba7
the reason is this is ancient software. Do we need this? I am temporarily reverting that commit for my HBD work in crashlab. I am told that reForis also has dependency on flup