After upgrading CloudForms appliance from 4.2 to 4.6, evm service is not starting and failing with rake aborted message.

Issue

• rake aborted after upgrade from 4.2 to 4.6

• After applying the procedure for migrating from 4.2 to 4.6, when I start evmserverd service, I have this error :

  Oct 23 16:54:06 xyzwr1 sh: rake aborted!
  Oct 23 16:54:06 xyzwr1 sh: ActiveRecord::SubclassNotFound: The single-table inheritance mechanism failed to locate the subclass:'ManageIQ::Providers::AnsibleTower::ConfigurationManager::RefreshWorker'. This error is raised because the column 'type' is reserved for storing the class in case of inheritance. Please rename this column if you didn't intend it to be used for storing the inheritance class or overwrite MiqWorker.inheritance_column to use another column for that information.