Settings: Don't crash if we pause too quickly

Notifier is unregistered in every case in pause.
However, if you close the Settings app too quick, the notifier
might not be registered at all, causing an IllegalArgumentException
during the unregistering.

Change-Id: I54141cbfc91d08c28ef524f4155b673ae8dee90e
[[3/4]/4] Settings: Audio Themes Settings

Change-Id: I8aad04a642441b91617943e6941841aec859396d

Conflicts:

	res/values/strings_crom.xml

Signed-off-by: hany <hany.alsamman@gmail.com>