Here's an updated patch to fix the crash in bug-ga2 when the system
has no configured ipv6 address. I have taken a different approach of
using libc_freeres_fn instead of the libc_freeres_ptr since the former
gives better control over what is freed; we need that since cache may
or may not be allocated using malloc.
Verified that bug-ga2 works correctly in both cases and does not have
memory leaks in either of them.
d62aa75af1