mksysinfo: Fix use of _in6_addr in _zone_net_addr_t.
mksysinfo: Fix use of _in6_addr in _zone_net_addr_t.

From Rainer Orth.

R=iant
CC=gofrontend-dev
https://golang.org/cl/5950043

qskycolor/gofrontend,anlhord/gofrontend,anlhord/gofrontend,qskycolor/gofrontend,golang/gofrontend,anlhord/gofrontend,anlhord/gofrontend,qskycolor/gofrontend,golang/gofrontend,anlhord/gofrontend,qskycolor/gofrontend,qskycolor/gofrontend,golang/gofrontend,anlhord/gofrontend,anlhord/gofrontend,qskycolor/gofrontend,qskycolor/gofrontend,golang/gofrontend