getnameinfo: fix calling __dns_parse with potentially too large rlen

__res_send returns the full answer length even if it didn't fit the
buffer, but __dns_parse expects the length of the filled part of the
buffer.

This is analogous to commit 77327ed064bd57b0e1865cd0e0364057ff4a53b4,
which fixed the only other __dns_parse call site.
1 file changed