Code review comment for lp:~seb128/phone-app/ringtone-in-gsettings

Those changes are making the sounds to use for call/messages to be read from gsettings/customizable, see https://bugs.launchpad.net/phone-app/+bug/1202253 for some details

Note that I've not been able to actual test the runtime behaviour, because I don't have a working phone with a SIM ... is there any way to simulate phone calls on a desktop? The code build and is working fine in a standalone test application.