Fix NPE when message is null in the response
Fix NPE when message is null in the response

killbill/killbill-cybersource-plugin,SquareMike/killbill-cybersource-plugin,killbill/killbill-cybersource-plugin,killbill/killbill-cybersource-plugin,SquareMike/killbill-cybersource-plugin,SquareMike/killbill-cybersource-plugin