npe fix: http://forum.yacy-websuche.de/viewtopic.php?t=1646

git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@5393 6c8d7289-2bf4-0310-a012-ef5d649a1542

source/de/anomic/data/bookmarksDB.java

@@ -537,6 +537,7 @@ public class bookmarksDB {
      * @param tag an object of type Tag to be stored/removed
      */
     public void storeTag(final Tag tag){
+    	if (tag == null) return;
         try {
             if(tag.size() >0){
                 bookmarksDB.this.tagsTable.put(tag.getTagHash(), tag.getMap());