Update duo_openvpn.c
Update duo_openvpn.c

don't overwrite what openvpn does with sig_chld. this breaks waitpid() for subsequent scripts, for example.

just make sure the called script always dies properly, else deal with zombies.
gdestuynder/duo_openvpn-1,limed/duo_openvpn,mozilla-it/duo_openvpn,limed/duo_openvpn,gdestuynder/duo_openvpn-1