CRM-14965 - Fix Search Builder notice : Notice: Only variable references should be returned by reference in CRM_Contact_Form_Search_Builder->convertFormValues()

https://issues.civicrm.org/jira/browse/CRM-14965
Merge pull request #3639 from atif-shaikh/CRM-14965

CRM-14965 - Fix Search Builder notice : Notice: Only variable references...