Comment 38 for bug 20960

It just happened again (on a fresh install of 5.10RC + apt-get upgrade), and my
/etc/network/interfaces reads as follows:

# The loopback network interface
auto lo
iface lo inet loopback

# This is a list of hotpluggable network interfaces.
# They will be activated automatically by the hotplug subsystem.
mapping hotplug
        script grep
        map eth1

# The primary network interface
iface eth1 inet dhcp
        # wireless-* options are implemented by the wireless-tools package
        wireless-mode managed
        wireless-essid xxx
        wireless-key1 xxx