cleanup.js : delete backup .cnf files in nodeX/

Could we update cleanup.js to include files such as:

./node4/node.0.cnf ./node5/node.3.cnf ./node5/node.2.cnf ./node5/node.1.cnf ./node5/node.0.cnf ./node6/node.0.cnf ./node7/node.0.cnf ./node8/node.0.cnf