eth0 error after installing Ubuntu Server 14.04.3 due to re-named eth0

[Colin Law]

I have just installed my first Ubuntu Server, 14.04.3 from
ubuntu-14.04.3-server-amd64.iso (previous systems have all been
desktop).  The install went ok and it had no trouble accessing the
network.  On booting however the network did not function and in
syslog I see

Nov  1 14:23:51 dibbler-s kernel: [    2.917909] r8169 0000:06:00.0
eth0: RTL8105e at 0xffffc9000476e000, 00:9c:02:20:38:c7, XID 00a00000
IRQ 28
Nov  1 14:23:51 dibbler-s kernel: [    3.086027] r8169 0000:06:00.0
em1: renamed from eth0
Nov  1 14:23:51 dibbler-s kernel: [    3.099888] systemd-udevd[111]:
renamed network interface eth0 to em1
and
Nov  1 14:23:53 dibbler-s dhclient: Error getting hardware address for
"eth0": No such device

When I look in /etc/network/interfaces I saw
auto lo
iface lo inet loopback
auto eth0
iface eth0 inet dhcp

Replacing the last two lines with
auto em1
iface em1 inet dhcp
and restarting networking caused it to work.

It seems to me this must be a bug but I cannot find anything in launchpad.

Any thoughts?

Colin