Service retirement of Ansible playbook or tower type is not working.

Issue

• Retirement of Ansible Playbook service using Embedded Ansible fails.
• Scheduled service retirement throws error only for ServiceAnsibleTower service type. With regular services it works fine.

• Error in the evm.log file:

  [----] E, [2020-02-19T23:26:08.837772 #30642:55ef60] ERROR -- : MIQ(MiqQueue#deliver) Message id: [1000131631546], Error: [uninitialized constant ServiceAnsibleTowerRetireRequest]
  [----] E, [2020-02-19T23:26:08.838213 #30642:55ef60] ERROR -- : [NameError]: uninitialized constant ServiceAnsibleTowerRetireRequest  Method:[block (2 levels) in <class:LogProxy>]
  
  OR
  
  [----] E, [2019-07-19T14:36:51.129935 #12894:fa0f64] ERROR -- : MIQ(MiqQueue#deliver) Message id: [10000000008587], Error: [uninitialized constant ServiceAnsiblePlaybookRetireRequest]
  [----] E, [2019-07-19T14:36:51.130191 #12894:fa0f64] ERROR -- : [NameError]: uninitialized constant ServiceAnsiblePlaybookRetireRequest  Method:[block (2 levels) in <class:LogProxy>]