go: mention the golang sources in process.go

Signed-off-by: Andrew Vagin <avagin@openvz.org>
test: fix tests accoding with the new api

Signed-off-by: Andrew Vagin <avagin@openvz.org>
util: use the right descriptor in close_fds

Signed-off-by: Andrey Vagin <avagin@openvz.org>