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.
@fryguy making changes as suggested, i compared with the code prior to refactoring of this code and it seems we dont need exp[exp_value_key][exp_value_index].split(' ').last