Fixing sonar issues in whole class
https://sonar.onap.org/dashboard/index?id=org.onap.appc%3Aappc-iaas-adapter-bundle%3Asrc%2Fmain%2Fjava%2Forg%2Fonap%2Fappc%2Fadapter%2Fiaas%2Fimpl%2FTenantCache.java