fix: flushDirtyRows will not throw an error when no dirty rows

Author: dachev

Diff for: src/features/row-edit/js/gridRowEdit.js

@@ -393,7 +393,7 @@
          */
         flushDirtyRows: function(grid){
           var promises = [];
-          grid.rowEdit.dirtyRows.forEach( function( gridRow ){
+          grid.api.rowEdit.getDirtyRows().forEach( function( gridRow ){
             service.saveRow( grid, gridRow )();
             promises.push( gridRow.rowEditSavePromise );
           });

Diff for: src/features/row-edit/test/uiGridRowEditService.spec.js

@@ -530,6 +530,12 @@ describe('ui.grid.edit uiGridRowEditService', function () {
       expect( success ).toEqual(false);
       expect( failure ).toEqual(true);
     });
+    
+    it( 'no dirty rows, no error is thrown', function() {
+      expect(function() {
+        uiGridRowEditService.flushDirtyRows( grid );
+      }).not.toThrow();
+    });
   });