audio: play tone when calling

Fixes regression introduced by b1539bd1. Since Tone was now in a
shared_ptr, reset was called on the shared_ptr instead of the Tone.

Change-Id: If2041feb8cffbb62f1748867a5099c2a0718de1d

src/media/audio/sound/tonelist.cpp

@@ -103,7 +103,7 @@ void
 TelephoneTone::setCurrentTone(Tone::TONEID toneId)
 {
     if (toneId != Tone::TONE_NULL && currentTone_ != toneId)
-        tones_[toneId].reset();
+        tones_[toneId]->reset();
 
     currentTone_ = toneId;
 }