mdevctl prevents hypervisor snap from starting

[Mark Beierl]

journalctl for snap.openstack-hypervisor.libvirtd shows the following if mdevctl deb package is installed:

○ snap.openstack-hypervisor.libvirtd.service - Service for snap application openstack-hypervisor.libvirtd
     Loaded: loaded (/etc/systemd/system/snap.openstack-hypervisor.libvirtd.service; enabled; vendor preset: enabled)
     Active: inactive (dead) since Thu 2023-05-25 20:37:47 UTC; 19h ago
   Main PID: 1682308 (code=exited, status=0/SUCCESS)
        CPU: 140ms

May 25 20:37:47 mark-t7600 systemd[1]: Started Service for snap application openstack-hypervisor.libvirtd.
May 25 20:37:47 mark-t7600 libvirtd[1682308]: libvirt version: 8.0.0
May 25 20:37:47 mark-t7600 libvirtd[1682308]: hostname: mark-t7600
May 25 20:37:47 mark-t7600 libvirtd[1682308]: error from service: GDBus.Error:org.freedesktop.DBus.Error.AccessDenied: An AppArmor policy prevents this sender from sending this message to this recipient; type="method_call", sender=":1.466" (uid=0 pid=1682308 comm="/snap/openstack-hypervisor/81/usr/sbin/libvirtd --" label="snap.openstack-hypervisor.libvirtd (enforce)") interface="org.freedesktop.DBus" member="ListActivatableNames" error name="(unset)" requested_reply="0" destination="org.freedesktop.DBus" (bus)
May 25 20:37:47 mark-t7600 libvirtd[1682308]: internal error: Unable to monitor directory: Error opening directory '/etc/mdevctl.d': Permission denied
May 25 20:37:47 mark-t7600 libvirtd[1682308]: Initialization of udev state driver failed: internal error: Unable to monitor directory: Error opening directory '/etc/mdevctl.d': Permission denied
May 25 20:37:47 mark-t7600 libvirtd[1682308]: Driver state initialization failed
May 25 20:37:47 mark-t7600 systemd[1]: snap.openstack-hypervisor.libvirtd.service: Deactivated successfully.

Purging the package allows it to start.