daemon: consider only address in kill_some_child()

daemon: consider only address in kill_some_child()

kill_some_child() compares the entire sockaddr_storage
structure (with the pad-bits zeroed out) when trying to
find out if connections originate from the same host.
However, sockaddr_storage contains the port-number for
the connection (which varies between connections), so
the comparison always fails.

Change the code so we only consider the host-address,
by introducing the addrcmp()-function that inspects
the address family and compare as appropriate.

Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>