Description of problem:
After Overriding the value of Smart class Parameter and validating the new default value with validator type 'list' fails.

Version-Release number of selected component (if applicable):
foreman-1.10.0-0.develop.201510011619git0033595.el7.noarch
foreman-release-scl-1-1.el7.x86_64

How reproducible:
Always

Steps to Reproduce:
1. Override the default value of a smart class parameter.
2. Select the key type as array/string.
3. Give new default value as [1]/1. (Just an example, anything can be provided)
4. In Optional Input Validator, Select validator type as list.
5. In Validator Rule, give some list of values in which the new default value should be present. In my case its [1,2].
6. Try to submit this change.

Actual results:
1. Validation Failed.
2. Not allowing to submit the change and labelling '[1] is not one of [1,2]' or '1 is not one of [1,2]' for Default Value field.

Expected results:
Should be allowed to submit the change and validation should pass as obvious in above case.