Unable to start rh-postgresql95-postgresql service during upgrade of RHVM to 4.2 while running engine-setup.

Issue

• After upgrading the RHVM packages to version 4.2, engine-setup fails with following error:

2018-06-22 08:13:40,858+0000 DEBUG otopi.plugins.otopi.services.systemd systemd.state:130 starting service rh-postgresql95-postgresql
2018-06-22 08:13:40,858+0000 DEBUG otopi.plugins.otopi.services.systemd plugin.executeRaw:813 execute: ('/bin/systemctl', 'start', 'rh-postgresql95-postgresql.service'), executable='None', cwd='None', env=None
2018-06-22 08:13:41,921+0000 DEBUG otopi.plugins.otopi.services.systemd plugin.executeRaw:863 execute-result: ('/bin/systemctl', 'start', 'rh-postgresql95-postgresql.service'), rc=1
2018-06-22 08:13:41,922+0000 DEBUG otopi.plugins.otopi.services.systemd plugin.execute:921 execute-output: ('/bin/systemctl', 'start', 'rh-postgresql95-postgresql.service') stdout:

2018-06-22 08:13:41,922+0000 DEBUG otopi.plugins.otopi.services.systemd plugin.execute:926 execute-output: ('/bin/systemctl', 'start', 'rh-postgresql95-postgresql.service') stderr:
Job for rh-postgresql95-postgresql.service failed because the control process exited with error code. See "systemctl status rh-postgresql95-postgresql.service" and "journalctl -xe" for details.

2018-06-22 08:13:41,923+0000 DEBUG otopi.transaction transaction._prepare:66 exception during prepare phase
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/otopi/transaction.py", line 62, in _prepare
    element.prepare()
  File "/usr/share/ovirt-engine/setup/ovirt_engine_setup/engine_common/postgres.py", line 849, in prepare
    state=True,
  File "/usr/share/otopi/plugins/otopi/services/systemd.py", line 141, in state
    service=name,
RuntimeError: Failed to start service 'rh-postgresql95-postgresql'
2018-06-22 08:13:41,924+0000 DEBUG otopi.context context._executeMethod:143 method exception
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/otopi/context.py", line 133, in _executeMethod
    method['method']()
  File "/usr/share/ovirt-engine/setup/bin/../plugins/ovirt-engine-setup/ovirt-engine/db/dbmsupgrade.py", line 89, in _updateDBMS
    oengcommcons.ProvisioningEnv.OLD_POSTGRES_SERVICE
  File "/usr/lib/python2.7/site-packages/otopi/transaction.py", line 106, in append
    self._prepare(element=element)
  File "/usr/lib/python2.7/site-packages/otopi/transaction.py", line 62, in _prepare
    element.prepare()
  File "/usr/share/ovirt-engine/setup/ovirt_engine_setup/engine_common/postgres.py", line 849, in prepare
    state=True,
  File "/usr/share/otopi/plugins/otopi/services/systemd.py", line 141, in state
    service=name,
RuntimeError: Failed to start service 'rh-postgresql95-postgresql'
2018-06-22 08:13:41,925+0000 ERROR otopi.context context._executeMethod:152 Failed to execute stage 'Misc configuration': Failed to start service 'rh-postgresql95-postgresql'