use less proccesses in process pool

source/net/yacy/kelondro/blob/ArrayStack.java

@@ -124,8 +124,8 @@ public class ArrayStack implements BLOB {
 
         // init the thread pool for the keeperOf executor service
         this.executor = new ThreadPoolExecutor(
-        		Runtime.getRuntime().availableProcessors() + 1,
+        		1,
-        		Runtime.getRuntime().availableProcessors() * 4, 100,
+        		Runtime.getRuntime().availableProcessors(), 100,
         		TimeUnit.MILLISECONDS,
         		new LinkedBlockingQueue<Runnable>(),
         		new NamePrefixThreadFactory(prefix));