Startup hook should implement SlingRepositoryInitializer to propagate

exceptions properly

This closes #545 partially

Author: kwin

accesscontroltool-startuphook-bundle/src/main/java/biz/netcentric/cq/tools/actool/startuphook/impl/AcToolStartupHookServiceImpl.java

@@ -56,7 +56,6 @@ public enum StartupHookActivation {
     @Reference(policyOption = ReferencePolicyOption.GREEDY)
     private AcInstallationService acInstallationService;
 
-    private boolean isCompositeNodeStore;
     private Config.StartupHookActivation activationMode;
 
     @Activate
@@ -115,7 +114,7 @@ private void copyAcHistoryToOrFromApps(SlingRepository repository, boolean isClo
             try {
                 session = repository.loginService(null, null);
 
-                if(isCompositeNodeStore) {
+                if(RuntimeHelper.isCompositeNodeStore(session)) {
                     LOG.info("Restoring history from /apps to /var");
 
                     if(session.nodeExists(HistoryUtils.AC_HISTORY_PATH_IN_APPS)) {