Comment 4 for bug 1633479

So I'm not convinced that doing this in dhclient is necessarily right. Unlike IPv4 where DHCP operates over a raw socket, in IPv6 mode, dhclient is just a regular network client and as such requires a source address to be set so it can contact the network (the link-local address in this case).

As dhclient is supposed to only be triggered after a RA has been received and parsed, it should be the job of whatever handles the RA to wait until a viable link-local has been established before triggering dhclient.

That being said, since we don't seem to have anything that handles that first configuration step properly, this workaround certainly won't hurt and will fix the current race condition.