show the store location for a DB toString

git-svn-id: https://svn.apache.org/repos/asf/activemq/trunk@1157118 13f79535-47bb-0310-9956-ffa450edef68

activemq-core/src/main/java/org/apache/activemq/store/kahadb/KahaDBStore.java

@@ -100,6 +100,11 @@ public class KahaDBStore extends MessageDatabase implements PersistenceAdapter {
         this.transactionStore = new KahaDBTransactionStore(this);
     }
 
+    @Override
+    public String toString() {
+        return "KahaDB:[" + directory.getAbsolutePath() + "]";
+    }
+
     public void setBrokerName(String brokerName) {
     }