[mako] Telephony service crashes leave proximity sensor enabled when no call is active

[James Tait]

I had a situation where my phone screen was turned off, but covering the proximity sensor and exposing it again turned the screen back on. The led to the lock screen being activated while the phone was in my pocket. Making and ending a call stopped this behaviour. Further investigation and discussion highlighted that ofonod, telephony-service-approver and telephony-service-handler all had crash files present. It seems that when the telephony service is restarted after a crash, it doesn't restore the proximity sensor state.