Merge pull request #93 from zora-han/master

对zui.datagrid.js的两处意见

dist/lib/datagrid/zui.datagrid.js

@@ -1179,7 +1179,7 @@
         }
         var dataItem = rowIndex > 0 ? that.getDataItem(rowIndex - 1) : null;
         config.data = dataItem;
-        config.rowId = dataItem ? (dataItem.rowId || dataItem.id) : (rowIndex === 0 ? '#header' : rowIndex);
+        config.rowId = rowIndex === 0 ? '#header' : rowIndex;
         return config;
     };