Upgrading Red Hat Satellite v6.0.8 to v6.1.1 fails on "restart_services" for tomcat

Issue

During an upgrade of Red Hat Satellite v6.0.8 to v6.1.1, the "katello-installer --upgrade" will fail in some cases on "Upgrade Step: restart_services".
Subsequent runs of "katello-installer --upgrade" yield the same result.

celery init v10.0.
Using config script: /etc/default/pulp_workers
Stopping tomcat6: waiting for processes 2787 to exit
killing 2787 which did not stop after 60 seconds           [WARNING]
                                                           [  OK  ]
Starting tomcat6:                                          [  OK  ]
Stopping httpd:                                            [  OK  ]
Starting httpd:                                            [  OK  ]
Starting foreman-tasks:                                    [  OK  ]
Some services failed: tomcat6

[ERROR 2015-08-12 12:22:53 main] Upgrade step restart_services failed. Check logs for more information.
[DEBUG 2015-08-12 12:22:53 main] Exit with status code: 1 (signal was 1)
[ERROR 2015-08-12 12:22:53 main] Repeating errors encountered during run:
[ERROR 2015-08-12 12:22:53 main] mongod is stopped

[ERROR 2015-08-12 12:22:53 main] <NilClass> nil
[ERROR 2015-08-12 12:22:53 main] httpd is stopped