initial tun/tap ioctls.
TUNSETIFF/TUNGETIFF/TUNSETOFFLOAD. See 315952.



git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13297 a5019735-40e9-0310-863c-91ae7b9d1cf9
wire up 2 vhost ioctls. The kernel does not use any parameter


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13298 a5019735-40e9-0310-863c-91ae7b9d1cf9