This renames the bird and bird-openwrt packages to bird1, to make it
possible for bird2 (added in a subsequent commit) to coexist with it.
The packages are renamed to bird1-ipv{4,6} to avoid the confusion of
having packages named 'bird2', 'bird4' and 'bird6'.
Also bump to v1.6.4 as that contains important bug fixes.
Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
