tests/net-yy-netlink.c: robustify against os specific issues
tests/net-yy-netlink.c: robustify against os specific issues

* tests/net-yy-netlink.c (main): Pass a pointer to a real struct msghdr
as NULL doesn't work well on some systems.

cuviper/strace,cuviper/strace,Saruta/strace,Saruta/strace,cuviper/strace,Saruta/strace,Saruta/strace,Saruta/strace,cuviper/strace,cuviper/strace