Do not display background shape in fullscreen notification if there’s nothing in it

So nothing cover a photo when using AirPlay photo sharing
Improve AirPlay device visibility in iOS 7

For some reasons, my iPhone doesn’t always show mythtv as an AirPlay device, and more often than not only show it as an audio device.
After playing a lot with the various bonjour advertising data, what I can gather is:
- If AirPlay video reports a version >= 120.x; the iPhone will attempt to use FairPlay DRM no matter what RAOP reports (even if it reports no support for encryption)
- If there’s a mismatch of version between AirPlay video and RAOP: the iPhone 5 won’t show the video service
- If reporting a version < 110 in AirPlay video, then photo sharing doesn’t reliably work
- If bit 10 in features bitmask is cleared, it doesn’t reliably show up
So I set the AirPlay video version to 115.3 (made up value) that allows photo sharing, and RAOP also to 115.3 and it all seem to work nicely now