Wrong use of the empty() function causes this problem.
 - !empty($query) must be replaced by isset($query) && ($query != '')
 - !empty($values['query']) replaced by isset($values['query']) &&
($values['query'] != '')

Change-Id: I5dee9187f48fa3b3f1eeddd23bf29413bb6433c8
Signed-off-by: Son Nguyen <son.nguyen@catalyst.net.nz>