Added serialVersionUid to DBPointer to remove a compiler warning

Author: jyemin

src/main/com/mongodb/DBPointer.java

@@ -26,7 +26,7 @@
 @Deprecated
 public class DBPointer extends DBRefBase {
 
-    static final boolean D = Boolean.getBoolean( "DEBUG.DBPOINTER" );
+    private static final long serialVersionUID = -1977838613745447826L;
 
     /**
      *  CTOR used for testing BSON encoding.  Otherwise
@@ -41,7 +41,7 @@ public DBPointer(String ns, ObjectId id) {
     }
 
     DBPointer( DBObject parent , String fieldName , DB db , String ns , ObjectId id ){
-        super(db, ns, (Object)id);
+        super(db, ns, id);
 
         _parent = parent;
         _fieldName = fieldName;