where interface renaming is not supported (NetBSD), remember both of
our netdev name and the correspoinding kernel name separately.
the latter is necessary to talk with kernel using interface names.
eg. ifioctls, bpf
XXX there should be a proper way to query kernel name.
Ben Pfaff suggested ovs-appctl but this patch doesn't implement it. (yet)
Signed-off-by: YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp> Signed-off-by: Ben Pfaff <blp@nicira.com>