Fix ra.filtering-select.js ui.autocomplete implementation bug 

I had a bug with the `ra.filtering-select.js` plugin which tried to call :
```javascript
input.data("autocomplete")._renderItem = function(ul, item) { ... }
```
which lead to undefined method errors in javascript console.

By inspecting the `ui.autocomplete` behavior, I noticed the data field name may have been changed to `uiAutocomplete`

Changing the name of the data field in both `ra.filtering-select.js` calls worked so I thought submitting this patch could be useful.