Fixed refactored code to set date and time variable based on params that...

... came in.

Changed to set date variable from exp[exp_value_key][exp_value_index] only when params_time_key came in.

https://bugzilla.redhat.com/show_bug.cgi?id=1142711

@dclarizio please review/test.
Could this also just be done by changing the `||` to `&&`.  I think that's really all that's need to fix this issue.

This new code doesn't use `exp[exp_value_key][exp_value_index].split(' ').last` at all?  Is that correct.