> Did you try:
>
> virsh undefine  domain-id
>
> where domain-id is your vm name
Perfect, thanks Earl!  Here's the script in case anyone else might
find it useful.  Please post any improvements if you can see a way to
improve it.
#!/bin/bash
# Removes all KVM virtual machines from this host
# First destroy all running VMs
for i in $(virsh -q list | awk '{ print $2 }'); do
  virsh destroy $i;
  virsh undefine $i;
done;
# Next we delete their virtual disk images
rm -rf /var/lib/libvirt/images/*.img