Removing measurement files from the previous builds

Change-Id: I79667e753777d35a2bac3d0f38eb84f25904efab
diff --git a/jjb/pipeline/voltha-scale-measurements.groovy b/jjb/pipeline/voltha-scale-measurements.groovy
index 0033d3a..e58b19c 100644
--- a/jjb/pipeline/voltha-scale-measurements.groovy
+++ b/jjb/pipeline/voltha-scale-measurements.groovy
@@ -32,6 +32,7 @@
     stage('cleanup') {
       steps {
         sh '''
+          rm -rf voltha-devices.txt onos-ports.txt total-time.txt onu-activation.txt
           for hchart in \$(helm list -q | grep -E -v 'docker-registry|cord-kafka|etcd-operator');
           do
               echo "Purging chart: \${hchart}"