We received an IP address from DHCP server and configure it statically.
This is required if we continue to use network connectivity to access
the root device (for example via NBD or NFS).
The lease is not updated, though. This can cause trouble in networks
with low lease times. So let's flush the addresses if root filesystem
has been copied to RAM. A dhcp client in main system can handle the
network connectivity then.
Signed-off-by: Christian Hesse <mail@eworm.de>
