Fix define dummy mappings.

```vim
" Sample
NeoBundleLazy 'kana/vim-textobj-entire', {
  \ 'autoload' : {
  \   'mappings' : [
  \     ['vo',
  \      '<Plug>(textobj-entire-a)',
  \      '<Plug>(textobj-entire-i)']]},
  \ 'depends' : 'kana/vim-textobj-user'}
```
```vim
:map
o  <Plug>(textobj-entire-i) * :<C-U>call neobundle#autoload#mapping('<Plug>(textobj-entire-i)', 'textobj-entire', 'o')
o  <Plug>(textobj-entire-a) * :<C-U>call neobundle#autoload#mapping('<Plug>(textobj-entire-a)', 'textobj-entire', 'o')
x  <Plug>(textobj-entire-a) * :<C-U>call neobundle#autoload#mapping('<Plug>(textobj-entire-a)', 'textobj-entire', 'x')
```

`mode`をそのまま使用していた為に`{mapping2}`以降で`{mode}`の最後の1つしか定義されなかったので修正しました