fix boolean logic broken in r19398, see #21840

git-svn-id: https://josm.openstreetmap.de/svn/trunk@19402 0c6e7542-c601-0410-84e7-c038aed88b3b

Author: stoecker

src/org/openstreetmap/josm/gui/dialogs/relation/RelationEditor.java

@@ -152,8 +152,8 @@ public final boolean isDirtyRelation() {
 
     @Override
     public final boolean isDirtyRelation(boolean ignoreUninterestingTags) {
-        if (relation != null && relation.getDataSet() == null &&
-            relationSnapshot != null && relationSnapshot.getDataSet() == null) {
+        if (relation == null || relation.getDataSet() == null ||
+            relationSnapshot == null || relationSnapshot.getDataSet() == null) {
             return false;
         }