The File output node stores it settings locally, but the stereo settings
were not displayed, making users only able to use the default settings
of the node.

The cause of not displaying the buttons are was a NULL-pointer check in
uiTemplateImageFormatViews. The NULL pointer was used to check if
multiview was enabled. in case of the file output node this check was
performed by the node, so the nullpointer check could be ignored.