fixbug for match postfix contains two "."

```js
{
    expand: true,
    src: [PATH_SRC + APP_NAME + '/*.js', PATH_SRC + APP_NAME + '/**/*.js'],
    dest: PATH_DEST,
    ext: '.js',
    rename: function(dest, src) { // console.log(src);
        var version = getVersion(src, PATH_TMP + APP_NAME + '.json', grunt);
        return version && (dest + version);
    }
}
```
I use the above code.
And if there has file like zepto.debug.js, then will outpu zepto.js in rename function.