bug: chk fails to check for iproute tools

[Sam Johnston <samjie@gmail.com>]

Morning all,

I lost access to a colo box yesterday because iproute wasn't
installed. Can someone please check this in as check_iproute (unless
you can see a good reason not to) so as to save someone else from
suffering the same fate.

#!/bin/bash
# CHECK-INSTALL

function error {
   echo 'Check for iproute (ip addr) failed.'
   exit 1
}

ip addr list || error

Thanks,

Sam