File dialog filters broken on Traits 4.2.0 with qt

```
from traits.etsconfig.api import ETSConfig
ETSConfig.toolkit = 'qt4'
from traits.api import HasTraits, File
from traitsui.api import View

class FEB(HasTraits):

correct = File(filter=['*.txt', '*.*'])
fubared = File(filter=['text files|*.txt', 'all files|*.*'])

traits_view = View('correct', 'fubared')

if __name__ == '__main__':
FEB().configure_traits()
```

In the above, the filter works for the `correct` file trait, but is broken for the `fubared`.