Description of problem:
HTTP PUT to /api/v2/hosts/bulk/install_content with `content_type` set to `package` seems not scheduling any tasks.
Same path with content_type `errata` works ok.


Version-Release number of selected component (if applicable):
6.2.1

How reproducible:
Always

Steps to Reproduce:
1. Make HTTP PUT request to /api/v2/hosts/bulk/install_content with some hosts and package as content type. Example of data: `{"organization_id": 19, "included": {"ids": [11, 12]}, "content": ["walrus-0.71-1.noarch"], "content_type": "package"}`
2.
3.

Actual results:
Received 200 response with body `{}`. No tasks for package installation were actually scheduled.

Expected results:
Received 202 response with message saying package was scheduled for installation. Package installation task for each affected host was actually scheduled.

Additional info:
production.log seems not containing anything interesting:
2016-09-09 06:49:35 2c1b7fda [app] [I] Started PUT "/api/v2/hosts/bulk/install_content" for 10.10.61.183 at 2016-09-09 06:49:35 -0400
2016-09-09 06:49:35 2c1b7fda [app] [I] Processing by Katello::Api::V2::HostsBulkActionsController#install_content as */*
2016-09-09 06:49:35 2c1b7fda [app] [I]   Parameters: {"organization_id"=>5, "included"=>{"ids"=>[2, 3]}, "content"=>["walrus-0.71-1.noarch"], "content_type"=>"package", "api_version"=>"v2", "hosts_bulk_action"=>{"organization_id"=>5, "included"=>{"ids"=>[2, 3]}, "content"=>["walrus-0.71-1.noarch"], "content_type"=>"package"}}
2016-09-09 06:49:35 2c1b7fda [app] [I] Authorized user admin(Admin User)
2016-09-09 06:49:36 2c1b7fda [app] [I]   Rendered /opt/theforeman/tfm/root/usr/share/gems/gems/katello-3.2.0/app/views/katello/api/v2/hosts_bulk_actions/job.json.rabl within katello/api/v2/layouts/resource (1.6ms)
2016-09-09 06:49:36 2c1b7fda [app] [I] Completed 200 OK in 555ms (Views: 16.5ms | ActiveRecord: 18.7ms)