Fixed prepopulator response for NUM_HH #3758

The prepopulator 
"prepopulated_should_show_num_hh_group" had its
values revered. The NUM_HH group should show if
there AREN'T any previous responses for NUM_HH.
In other words, the prepopulator should indicate
"FALSE" when previous NUM_HH exist.
simplified method return #3758
Merge pull request #243 from NUBIC/bug_3758_q_prepopulated_should_show_num_hh_group_is_not_evaluated

Fixed prepopulator response for NUM_HH #3758