@Override
  public void finalizeModule() {
    finalizeChildModules(serviceModules.values());
    finalizeChildModules(configurationModules.values());
  }
Fully resolve the extension. See extension resolution description in the class documentation.
If the extension has a parent, this extension will be merged against its fully resolved parent
if one is specified. Merging applies to all extension state including child service and
configuration modules.  Services may extend a service in another version in the
same extension hierarchy or may explicitly extend a service in a different
hierarchy.

@param parentModule   not used.  Each extension determines its own parent since extensions don't
                      have containing modules
@param allStacks      all stacks modules contained in the stack definition
@param commonServices all common services
@param extensions     all extensions

@throws AmbariException if an exception occurs during extension resolution
ambari-server/src/main/java/org/apache/ambari/server/stack/ExtensionModule.java