VOL-3180 Improve collection of OLT logs

Change-Id: I651c3c135939c76df2791984353194dfb9607cc2
diff --git a/Jenkinsfile-voltha-build b/Jenkinsfile-voltha-build
index b18c3c5..029a32d 100644
--- a/Jenkinsfile-voltha-build
+++ b/Jenkinsfile-voltha-build
@@ -219,7 +219,7 @@
                         timeout(5) {
                             sh returnStdout: true, script: """
                             ssh-keyscan -H ${deployment_config.olts[i].ip} >> ~/.ssh/known_hosts
-                            sshpass -p ${deployment_config.olts[i].pass} ssh -l ${deployment_config.olts[i].user} ${deployment_config.olts[i].ip} 'reboot' || true
+                            sshpass -p ${deployment_config.olts[i].pass} ssh -l ${deployment_config.olts[i].user} ${deployment_config.olts[i].ip} 'rm -f /var/log/openolt.log; rm -f /var/log/dev_mgmt_daemon.log; reboot' || true
                             sleep 120
                             """
                         }