Cloned from https://bugzilla.redhat.com/show_bug.cgi?id=1218504
Description of problem:
when you open add_interface modal window and click on info box, it doesn't expand. Also firebug raises:

"NetworkError: 500 Internal Server Error - https://dhcp201-172.englab.pnq.redhat.com/interfaces/new"

production.log: ===============

2015-05-05 11:54:48 [I] Processing by InterfacesController#new as JS
2015-05-05 11:54:48 [W] Operation FAILED: undefined method `fetch' for nil:NilClass
2015-05-05 11:54:48 [I] Rendered common/500.html.erb (4.8ms)
2015-05-05 11:54:48 [I] Completed 500 Internal Server Error in 22ms (Views: 5.5ms | ActiveRecord: 2.1ms)
2015-05-05 11:55:02 [I] Processing by InterfacesController#new as JS
2015-05-05 11:55:02 [W] Operation FAILED: undefined method `fetch' for nil:NilClass
2015-05-05 11:55:02 [I] Rendered common/500.html.erb (4.7ms)
2015-05-05 11:55:02 [I] Completed 500 Internal Server Error in 22ms (Views: 5.4ms | ActiveRecord: 2.1ms)

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

sat6.1 GA snap2(Satellite-6.1.0-RHEL-7-20150429.2)

How reproducible:
always

Steps to Reproduce:
1. New_host --> add_interface --Device_identifier info_box/tool_tip
2.
3.

Actual results:
Operation FAILED: undefined method `fetch' for nil:NilClass in production.log
Couldn't open Device_identifier info_box on clicking it

Expected results:
on click, Device_identifier info_box should be expanded and no error thrown in logs

Additional info: