Added functionality in apprtc demo to close the capture device on hangup.

BUG=1589
R=juberti@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/2018004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@4540 4adac7df-926f-26a2-2b94-8c16560cd09d

samples/js/apprtc/js/main.js

@@ -312,6 +312,7 @@
   function onHangup() {
     console.log('Hanging up.');
     transitionToDone();
+    localStream.stop();
     stop();
     // will trigger BYE from server
     socket.close();