daemon: fix IPv6 address truncation in ip2str()

daemon: fix IPv6 address truncation in ip2str()

The sockaddr struct size (ai_addrlen) is passed as the output buffer
size to inet_ntop(). For IPv6, sizeof(sockaddr_in6) is 28 bytes but
INET6_ADDRSTRLEN is 46, so long IPv6 addresses are silently truncated.

Fix this by passing sizeof(ip) instead, which is the actual size of
the destination buffer. Drop the now-unused len parameter from
ip2str() and update all callers.

Signed-off-by: Sebastien Tardif <sebtardif@ncf.ca>
Signed-off-by: Junio C Hamano <gitster@pobox.com>