need ebtables-save && ebtables-restore, ebtables debian package don't include them.
ebtables-restore need to restore the full ruleset (atomicaly),
so we can't update only 1 chain
Signed-off-by: Alexandre Derumier <aderumier at odiso.com> Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com> Reviewed-by: Thomas Lamprecht <t.lamprecht@proxmox.com> Tested-by: Thomas Lamprecht <t.lamprecht@proxmox.com>