Cloned from https://bugzilla.redhat.com/show_bug.cgi?id=1297736
Description of problem:
The 'Hidden Value' checkbox is disabled for Parameter having empty puppet default value.

Version-Release number of selected component (if applicable):
foreman-1.11.0-0.develop.201512111432git98f6ca5.el7.noarch

How reproducible:
Always

Steps to Reproduce:
1. Import a puppet class parameter with empty puppet default value.
2. In Config - > Smart Class Parameters - > Parameter - > Check Override Button.
3. Don't set any default value. leave it as blank only.
4. Check 'Hidden Value' checkbox.

Actual results:
The 'Hidden Value' checkbox is disabled to check.

Expected results:
The 'Hidden Value' checkbox should be enabled even if puppet default value empty.

Additional info: