public void removeExtension(ExtensionInfo extension) {
    Collection<ExtensionInfo> extensions = getExtensions();
    extensions.remove(extension);
    Collection<ServiceInfo> services = getServices();
    for (ServiceInfo service : extension.getServices()) {
      services.remove(service);
    }
  }
@return A list containing all repos for this stack, grouped by os
ambari-server/src/main/java/org/apache/ambari/server/state/StackInfo.java