This fixes an issue where attempting to use "!=" in a condition with an array with only a single element generates invalid SQL.

Example:
$condition['Model.id !='] = array(1, 2); //Generates `Model`.`id` NOT IN (1, 2) as expected

$condition['Model.id !='] = array(1); //Generates `Model`.`id` != = (1) which is invalid SQL

Patch will cause the above to generate `Model`.`id` != (1);