Added improvement for MP and corrected the ESBJAVA-3047

Patch given for ESBJAVA-3047 is not properly merged in [1], so Corrected the code accordingly

[1]https://github.com/wso2/wso2-synapse/commit/2fc7859382fbbe1967879327a87069df716b6582


Added improvement for Message Processor to support drop the message after max retry attempt ESBJAVA-2908