Fixing sonar issues in whole class
https://sonar.onap.org/dashboard/index?id=org.onap.appc%3Aappc-artifact-handler-provider%3Asrc%2Fmain%2Fjava%2Forg%2Fonap%2Fappc%2Fartifact%2Fhandler%2Fnode%2FArtifactHandlerNode.java