Make sure out counts our current before attempting to use them for sorting

git-svn-id: http://google-refine.googlecode.com/svn/trunk@2347 7d457c2a-affb-35e4-300a-418c747d4874

main/src/com/google/refine/importers/tree/TreeImportingParserBase.java

@@ -89,6 +89,7 @@ abstract public class TreeImportingParserBase implements ImportingParser {
             }
         }
         
+        rootColumnGroup.tabulate();
         XmlImportUtilities.createColumnsFromImport(project, rootColumnGroup);
         project.columnModel.update();
     }