daemon.c: avoid accessing ss_family member of struct sockaddr_storage

daemon.c: avoid accessing ss_family member of struct sockaddr_storage

When NO_SOCKADDR_STORAGE is set for a platform, either sockaddr_in or
sockaddr_in6 is used intead.  Neither of which has an ss_family member.
They have an sin_family and sin6_family member respectively.  Since the
addrcmp() function accesses the ss_family member of a sockaddr_storage
struct, compilation fails on platforms which define NO_SOCKADDR_STORAGE.

Since any sockaddr_* structure can be cast to a struct sockaddr and
have its sa_family member read, do so here to workaround this issue.

Thanks to Martin Storsjö for pointing out the fix, and Gary Vaughan
for drawing attention to the issue.

Signed-off-by: Brandon Casey <casey@nrlssc.navy.mil>
Signed-off-by: Junio C Hamano <gitster@pobox.com>