[tripleo][ussuri][undercloud][tripleo_rabbitmq] do not start after reboot

Hi all,

I think this issue might be known to RHOSP16 [1], but it is same in RDO - ussuri with centos8. if anything is needed, I could try to help/test.

my workaround is to run openstack undercloud install --force-stack-update

[1] https://access.redhat.com/solutions/5269241