Fix attribute form choice type error.

| Q	                       | A     |
|--------------------------|------ |
| Bug Fix?        	| yes     |
| New Feature?	| n     |
| BC Breaks?	       | n     |
| Deprecations?	| n     |
| Tests Pass?	       | n     |
| Fixed Tickets	       | #249 #417 #651 #743 #1845 #2006 |
| License	               | MIT |
| Doc PR                  |        |

This's still not perfect solution but can fix many issues for now.
@stloyd You are right, We can use:

```php
$choices = $data['choices'];
```