s390x: Re-add RawSockaddrUnix structure

[michael-holzheu]

The structure has been removed by commit c88ed9c5c9a ("update vendor") for mips64, mips64_le, and s390x.

This leads to the following build error on s390x:

$ make
go build -tags "static_build  with_libvirt" -o runv .
# github.com/hyperhq/runv/vendor/golang.org/x/sys/unix
vendor/golang.org/x/sys/unix/syscall_unix.go:165: undefined: RawSockaddrVsock
make: *** [build-runv] Error 2

So re-add the structure to fix the build error.

Signed-off-by: Michael Holzheu holzheu@linux.vnet.ibm.com

[michael-holzheu]

Thanks for merging!