CRM-14968

Fix For https://issues.civicrm.org/jira/browse/CRM-14968?focusedCommentId=66281&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-66281

CRM_Utils_Array returns NULL(if 'payment_processor' is not present in $params) which makes the condition TRUE on matching with 0, hence used !empty to check in a proper manner.