input[type="file"] defaults to textInput directive; conflicts w/ custom directive

[igienger]

Overview:
File uploads are a complex issue, so AngularJS v1 leaves it up to others to implement:
#1375 (comment)

This hasn't been much of a problem, but recently textInput directive has started clobbering the view value:
a090400

The textInput directive has been applied to file input elements by default for a long time, but since that change it always adds an onchange listener, so depending on directive ordering, the textInput directive's listener can be called last and clobber the view value.

Repro: http://jsfiddle.net/mR3P6/6/

Suggested Fix:
I don't think file input elements should have the textInput directive applied at all. I think it should be a noop, just like the hidden, button, submit, or reset types.

[IgorMinar]

@tbosch can you please look into this?

[caitp]

This should be fairly easy to fix, but I'm not totally sure how this could be tested. I tend to agree though, it (input[type=file]) really should be noop'd rather than use the textInputType function

[djvs]

see a9fcb0d for problems introduced by this change