Internal span of file upload component remains disabled

[VDubber]

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Plunkr Case (Bug Reports)
http://plnkr.co/edit/wkcf4RCj03ecMZJfIZ7V?p=preview

Current behavior
When the input attribute disabled is set to false, a internal span remains disabled.

<span class="ui-fileupload-choose ui-button ui-widget ui-state-default ui-corner-all ui-button-text-icon-left" icon="fa-plus" pbutton="" ng-reflect-klass="ui-fileupload-choose" ng-reflect-ng-class="[object Object]" ng-reflect-label="Choose" ng-reflect-icon="fa-plus"
          disabled="false"> 
       ...
</span>

Expected behavior
Internal span does not have disabled attribute applied when component input disabled attribute is false.

Minimal reproduction of the problem with instructions
Create a fileUpload component with [disabled]="false"
DOM indicates that the span is disabled.
By w3c standards, the presence of the disabled attribute is what actually disables the element.

What is the motivation / use case for changing the behavior?
Styles meant to be applied to disabled elements are misapplied.