Unit test coverage for ActionIdentifiers.java
Sonar Link: https://sonar.onap.org/code?id=org.onap.appc%3Aappc&selected=org.onap.appc%3Adomain-model-lib%3Asrc%2Fmain%2Fjava%2Forg%2Fonap%2Fappc%2Fdomainmodel%2Flcm%2FActionIdentifiers.java