Remove two linter warnings
Remove two linter warnings

> /home/travis/build/vellotis/bookshelf/src/sync.js
>   warning  Trailing spaces not allowed  no-trailing-spaces
>   warning  Trailing spaces not allowed  no-trailing-spaces
>
> ✖ 2 problems (0 errors, 2 warnings)

bookshelf/bookshelf,tgriesser/bookshelf,seegno-forks/bookshelf,tgriesser/bookshelf,rbong/bookshelf,rbong/bookshelf,seegno-forks/bookshelf,TinOo512/bookshelf,bookshelf/bookshelf,TinOo512/bookshelf