Forget speakerphone state when calls disconnect.

Bug: 15433058
Change-Id: Ib0d31cebc31565b73e297635e021eda621cef760
diff --git a/src/com/android/telecomm/CallAudioManager.java b/src/com/android/telecomm/CallAudioManager.java
index 979a51a..e53de84 100644
--- a/src/com/android/telecomm/CallAudioManager.java
+++ b/src/com/android/telecomm/CallAudioManager.java
@@ -74,6 +74,7 @@
         if (CallsManager.getInstance().getCalls().isEmpty()) {
             Log.v(this, "all calls removed, reseting system audio to default state");
             setInitialAudioState(null);
+            mWasSpeakerOn = false;
         }
         updateAudioStreamAndMode();
     }