Description of problem:
The novajoin_enrollment tests return code 500 'No valid host was found' error.

{1} novajoin_tempest_plugin.tests.scenario.test_novajoin_enrollment.ServerTest.test_enrollment_metadata_in_image [10.836171s] ... FAILED
{1} novajoin_tempest_plugin.tests.scenario.test_novajoin_enrollment.ServerTest.test_enrollment_metadata_in_instance [10.716608s] ... FAILED

Captured traceback:
~~~~~~~~~~~~~~~~~~~
    b'Traceback (most recent call last):'
    b'  File "/usr/lib/python3.6/site-packages/novajoin_tempest_plugin/tests/scenario/test_novajoin_enrollment.py", line 169, in test_enrollment_metadata_in_image'
    b"    wait_until='ACTIVE')"
    b'  File "/usr/lib/python3.6/site-packages/novajoin_tempest_plugin/tests/scenario/manager.py", line 122, in create_server'
    b"    'ACTIVE')"
    b'  File "/usr/lib/python3.6/site-packages/tempest/common/waiters.py", line 76, in wait_for_server_status'
    b'    server_id=server_id)'
    b'tempest.exceptions.BuildErrorException: Server 26850630-38c6-4382-8072-78537cafa908 failed to build and is in ERROR status'
    b'Details: {\'code\': 500, \'created\': \'2019-07-15T17:22:28Z\', \'message\': \'No valid host was found. \', \'details\': \'  File "/usr/lib/python3.6/site-packages/nova/conductor/manager.py", line 1352, in schedule_and_build_instances\\n    instance_uuids, return_alternates=True)\\n  File "/usr/lib/python3.6/site-packages/nova/conductor/manager.py", line 806, in _schedule_instances\\n    return_alternates=return_alternates)\\n  File "/usr/lib/python3.6/site-packages/nova/scheduler/client/query.py", line 42, in select_destinations\\n    instance_uuids, return_objects, return_alternates)\\n  File "/usr/lib/python3.6/site-packages/nova/scheduler/rpcapi.py", line 160, in select_destinations\\n    return cctxt.call(ctxt, \\\'select_destinations\\\', **msg_args)\\n  File "/usr/lib/python3.6/site-packages/oslo_messaging/rpc/client.py", line 178, in call\\n    retry=self.retry)\\n  File "/usr/lib/python3.6/site-packages/oslo_messaging/transport.py", line 128, in _send\\n    retry=retry)\\n  File "/usr/lib/python3.6/site-packages/oslo_messaging/_drivers/amqpdriver.py", line 645, in send\\n    call_monitor_timeout, retry=retry)\\n  File "/usr/lib/python3.6/site-packages/oslo_messaging/_drivers/amqpdriver.py", line 636, in _send\\n    raise result\\n\'}'
    b''


Version-Release number of selected component (if applicable):
RHOS_TRUNK-15.0-RHEL-8-20190708.n.2

How reproducible:


Steps to Reproduce:
1. Deploy RHOS-15 with 'passed_phase1' or the latest puddle with topology controller:3,compute:2,freeipa:1,ironic:4
2. Install 'openstack-tempest-all' and 'python3-novajoin-tests-tempest' packages
3. source /home/stack/overcloudrc
4. On the undercloud /home/stack dir, create workspace for tempest

(undercloud) [stack@undercloud-0 ~]$ tempest init novajoin_tempest
2019-07-15 10:27:23.909 1025847 INFO tempest [-] Using tempest config file /etc/tempest/tempest.conf

5. change directory, cd novajoin_tempest
6. Configure the tempest.conf as per novajoin tempest tests 

discover-tempest-config --out etc/tempest.conf --deployer-input ~/tempest-deployer-input.conf --debug --create identity.uri $OS_AUTH_URL auth.admin_password $OS_PASSWORD auth.admin_username $OS_USERNAME auth.use_dynamic_credentials true network.tenant_network_cidr 172.17.2.0/24 validation.connect_method 'fixed' validation.network_for_ssh 'ctlplane' compute.allow_tenant_isolation 'True' object-storage.operator_role 'swiftoperator' novajoin.tripleo_controllers 'controller-0,controller-1,controller-2' novajoin.tripleo_computes 'compute-0,compute-1' novajoin.tripleo_undercloud 'undercloud-0' novajoin.flavor_tag baremetal image.image_path http://download-node-02.eng.bos.redhat.com/qa/rhts/lookaside/security-dfg/python-novajoin/Fedora-Cloud-Base-29-1.2.x86_64.qcow2 image.http_image http://download-node-02.eng.bos.redhat.com/qa/rhts/lookaside/security-dfg/python-novajoin/Fedora-Cloud-Base-29-1.2.x86_64.qcow2 validation.image_ssh_user fedora

7. execute novajoin tempest tests

(overcloud) [stack@undercloud-0 novajoin]$ tempest run --regex novajoin_tempest_plugin

Actual results:
{1} novajoin_tempest_plugin.tests.scenario.test_novajoin_enrollment.ServerTest.test_enrollment_metadata_in_image [10.836171s] ... FAILED
{1} novajoin_tempest_plugin.tests.scenario.test_novajoin_enrollment.ServerTest.test_enrollment_metadata_in_instance [10.716608s] ... FAILED

Expected results:
Tests pass/ok

Additional info: 
access the undercloud sos report here: https://drive.google.com/open?id=149fU1k9p52q9khOAWvprgiLxHbE8_T7P