Intermediate step in removal of Base

We are marking types that will be Nexters and ResultNexters (I want a
better name for this one).

graph/leveldb/iterator.go

@@ -62,7 +62,6 @@ func NewIterator(prefix string, d graph.Direction, value graph.Value, ts *Triple
 		open:           true,
 		ts:             ts,
 	}
-	iterator.BaseInit(&it.Base)
 
 	ok := it.iter.Seek(it.nextPrefix)
 	if !ok {
@@ -155,6 +154,10 @@ func (it *Iterator) Result() graph.Value {
 	return it.result
 }
 
+func (it *Iterator) NextResult() bool {
+	return false
+}
+
 // No subiterators.
 func (it *Iterator) SubIterators() []graph.Iterator {
 	return nil