rtnl_link_veth_add() is a helper API we provide, it makes sense to
set NLM_F_EXCL for it since it doesn't accept flags as a parameter.
BTW, correct an indention too.
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Thomas Haller <thaller@redhat.com>