Credential API V2 is breaking manageiq refresh

[jameswnl]

#107 brings in partial support of API V2 and set V2 to be the default. However, credential V2 is different from V1 and ManageIQ is based on V1. Refresh will fail.

224631 [----] E, [2018-07-23T17:35:06.576918 #93173:3fe7e88057b8] ERROR -- : MIQ(ManageIQ::Providers::AnsibleTower::AutomationManager::Refresher#refresh) EMS: [Tower32 Automation Manager], id: [1] Unable
       to perform refresh for the following targets:
224632 [----] E, [2018-07-23T17:35:06.577220 #93173:3fe7e88057b8] ERROR -- : MIQ(ManageIQ::Providers::AnsibleTower::AutomationManager::Refresher#refresh)  --- ManageIQ::Providers::AnsibleTower::Automation       Manager [Tower32 Automation Manager] id [1]
224633 [----] I, [2018-07-23T17:35:06.593831 #93173:3fe7e88057b8]  INFO -- : MIQ(ManageIQ::Providers::AnsibleTower::AutomationManager::Refresher#refresh) Refreshing all targets...Complete
224634 [----] E, [2018-07-23T17:35:06.594215 #93173:3fe7e88057b8] ERROR -- : MIQ(MiqQueue#deliver) Message id: [66], Error: [undefined method `username' for #<AnsibleTowerClient::CredentialV2:0x007fcfc4bf       f4c8>]
224635 [----] E, [2018-07-23T17:35:06.594562 #93173:3fe7e88057b8] ERROR -- : [ManageIQ::Providers::BaseManager::Refresher::PartialRefreshError]: undefined method `username' for #<AnsibleTowerClient::Crede       ntialV2:0x007fcfc4bff4c8>  Method:[block in method_missing]
224636 [----] E, [2018-07-23T17:35:06.594829 #93173:3fe7e88057b8] ERROR -- : /Users/dbomhof/syncrou/manageiq/app/models/manageiq/providers/base_manager/refresher.rb:67:in `refresh'

[jameswnl]

@miq-bot add_labels bug
@miq-bot assigns @bdunne

[bdunne]

Closed by #117