Comment 3 for bug 1732703

Trying to enlist a machine when systemd+upstart are installed in trusty, throws this error:

==> /var/log/maas/clusterd.log <==
2017-11-21 11:42:45+0000 [-] Unhandled failure dispatching AMP command. This is probably a bug. Please ensure that this error is handled within application code or declared in the signature of the RemoveHostMaps command. [trusty-maas:pid=844:cmd=RemoveHostMaps:ask=25]
        Traceback (most recent call last):
          File "/usr/lib/python2.7/threading.py", line 783, in __bootstrap
            self.__bootstrap_inner()
          File "/usr/lib/python2.7/threading.py", line 810, in __bootstrap_inner
            self.run()
          File "/usr/lib/python2.7/threading.py", line 763, in run
            self.__target(*self.__args, **self.__kwargs)
        --- <exception caught here> ---
          File "/usr/lib/python2.7/dist-packages/twisted/python/threadpool.py", line 191, in _worker
            result = context.call(ctx, function, *args, **kwargs)
          File "/usr/lib/python2.7/dist-packages/twisted/python/context.py", line 118, in callWithContext
            return self.currentContext().callWithContext(ctx, func, *args, **kw)
          File "/usr/lib/python2.7/dist-packages/twisted/python/context.py", line 81, in callWithContext
            return func(*args,**kw)
          File "/usr/lib/python2.7/dist-packages/provisioningserver/utils/twisted.py", line 200, in wrapper
            return func(*args, **kwargs)
          File "/usr/lib/python2.7/dist-packages/provisioningserver/rpc/dhcp.py", line 237, in remove_host_maps
            if not _is_dhcpv4_managed_and_active(CannotRemoveHostMap):
          File "/usr/lib/python2.7/dist-packages/provisioningserver/rpc/dhcp.py", line 164, in _is_dhcpv4_managed_and_active
            if service_monitor.get_service_state("dhcp4") != SERVICE_STATE.ON:
          File "/usr/lib/python2.7/dist-packages/provisioningserver/utils/twisted.py", line 200, in wrapper
            return func(*args, **kwargs)
          File "/usr/lib/python2.7/dist-packages/provisioningserver/service_monitor.py", line 120, in get_service_state
            return self._get_service_status(service)[0]
          File "/usr/lib/python2.7/dist-packages/provisioningserver/service_monitor.py", line 216, in _get_service_status
            service.service_name)
          File "/usr/lib/python2.7/dist-packages/provisioningserver/service_monitor.py", line 265, in _get_systemd_service_status
            service_name))
        provisioningserver.service_monitor.ServiceParsingError: Unable to parse the output from systemd for service 'maas-dhcpd'.

==> /var/log/maas/regiond.log <==
2017-11-21 11:42:45 [-] Error on request (63) node.create: ('UNHANDLED', 'Unknown Error [trusty-maas:pid=844:cmd=RemoveHostMaps:ask=25]')
        Traceback (most recent call last):
        Failure: twisted.protocols.amp.UnhandledCommand: ('UNHANDLED', 'Unknown Error [trusty-maas:pid=844:cmd=RemoveHostMaps:ask=25]')

A similar error is shown when trying to commission (same ServiceParsingError for maas-dhcpd). Removing systemd, or patching get_init_system() to detect the proper service file, makes the issue disappear.