Importing nodes before importing images results in error and traceback.

Environment:
puppet-ironic-14.2.0-0.20190115174142.b1d4930.el7.noarch
python2-ironic-lib-2.16.0-0.20181018091317.dd7e1fe.el7.noarch
python2-ironicclient-2.5.0-0.20181109051911.fb94fb8.el7.noarch
openstack-ironic-inspector-8.1.1-0.20190108145312.9a8cb3a.el7.noarch


Steps to reproduce:
1. Deploy undercloud
2. Try to import nodes before importing images


Result:
(undercloud) [stack@undercloud ~]$ openstack overcloud node import instackenv.json 
Waiting for messages on queue 'tripleo' with no timeout.
openstack baremetal Kernel image not found in Glance, and no path specified.
Exception occured while running the command
Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/tripleoclient/command.py", line 28, in run
    super(Command, self).run(parsed_args)
  File "/usr/lib/python3.6/site-packages/osc_lib/command/command.py", line 41, in run
    return super(Command, self).run(parsed_args)
  File "/usr/lib/python3.6/site-packages/cliff/command.py", line 184, in run
    return_code = self.take_action(parsed_args) or 0
  File "/usr/lib/python3.6/site-packages/tripleoclient/v1/overcloud_node.py", line 284, in take_action
    instance_boot_option=parsed_args.instance_boot_option
  File "/usr/lib/python3.6/site-packages/tripleoclient/workflows/baremetal.py", line 80, in register_or_update
    'Exception registering nodes: {}'.format(payload['message']))
tripleoclient.exceptions.RegisterOrUpdateError: Exception registering nodes: Kernel image not found in Glance, and no path specified.
Exception registering nodes: Kernel image not found in Glance, and no path specified.

Expected result:
A message stating that the images aren't found. No traceback.