Bug#1061757: subnetcalc outputs 6to4 value as stderr

[Sakirnth Nagarasa]

Package: subnetcalc
Version: 2.4.21-1

Hello

When I give a public IPv6 subnet as argument for subnetcalc the 6to4
address outputs as stderr.

To reproduce you can do:
subnetcalc ${public_ipv6_subnet} 2> stderr

Thanks and greetings
Saki