Allows the user to choose a nomination type (bug 1071228)

Only when all versions are deleted (STATUS==NULL) and he wants to upload a new one. Otherwise the choice field should remain hidden.
This doesn't seem necessary anymore (it was a fix from 2011, not sure why, but i could submit addons using chrome, and it was re-disabling the button in certain cases, like when submitting the form without a nomination type selected).