title: drop mediator in fault sequence is mandatory in wso2 esb 4.9.0
body: <p>We removed the drop mediator in default fault sequence and added payload factory to construct business specific message response. We noticed all ESB servers are going down when there are time outs from back end services. We tried to control servers going down with manipulating time outs on each back end services but no luck. We were thinking is there any issue in removing drop mediator from fault sequence</p>