Add decoding of sockets descriptor 'paths' for network calls

Add decoding of sockets descriptor 'paths' for network calls

* net.c (sys_bind, sys_listen, do_accept, sys_send, sys_sendto,
sys_sendmsg, sys_sendmmsg, sys_recv, sys_recvfrom, sys_recvmsg,
sys_recvmmsg, sys_shutdown, sys_getsockopt, sys_setsockopt): Decode
socket descriptor arguments using printfd.
* pathtrace.c (pathtrace_match): Also check TRACE_NETWORK syscalls
that take socket descriptor arguments.
* tests/net-fd.test: New test for socket descriptor arguments decoding.
* tests/Makefile.am (TESTS): Add net-fd.test.
(net-fd.log): New dependency on net.log.

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>