honor history cache setting

Author: vladak

opengrok-indexer/src/main/java/org/opengrok/indexer/history/HistoryGuru.java

@@ -1048,9 +1048,18 @@ public void storeHistory(File file, History history) {
     }
 
     private void createHistoryCache(Repository repository, String sinceRevision) throws CacheException, HistoryException {
+        // TODO: add test for this
+        if (!repository.isHistoryCacheEnabled()) {
+            LOGGER.log(Level.INFO,
+                    "Skipping history cache creation for {0} and its subdirectories: history cache disabled",
+                    repository);
+            return;
+        }
+
         if (!repository.isHistoryEnabled()) {
             LOGGER.log(Level.INFO,
-                    "Skipping history cache creation for {0} and its subdirectories", repository);
+                    "Skipping history cache creation for {0} and its subdirectories: history disabled",
+                    repository);
             return;
         }