Bluetooth shows "Not discoverable" when switching but not when entering/exiting

[Matthew Paul Thomas]

Ubuntu 15.04 r132

1. Navigate to System Settings > "Bluetooth", and turn on Bluetooth if it is off.
2. Switch to another app.
3. Switch back to System Settings.
4. Tap the Back button to the System Settings main screen.
5. Return to the "Bluetooth" screen.

What happens:
3. You see "Not discoverable", with a spinner, change to "Discoverable" after a second.
4. The navigation happens instantly.
5. You see "Discoverable" instantly.

What should happen:
3. You see "Not discoverable", with a spinner, change to "Discoverable" after a second.
4. You see "Not discoverable" for a second before System Settings returns to the main screen.
5. You see "Not discoverable", with a spinner, change to "Discoverable" after a second.

<https://wiki.ubuntu.com/Bluetooth#Discoverability>: "Whenever Bluetooth is on but you have been on the screen for less than one second, the status text should be 'Not discoverable' opposite a spinner ... If you navigate back to the System Settings overview, the status text should change immediately to “Not discoverable”, without a spinner, and System Settings should pause for one second so that you can see this."