Java VideoRenderer class may be backed by two different native
classes depending on type of rendering.
Fix crash in AppRtcDemo by calling correct destructor on exit.

BUG=
R=braveyao@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/23699004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7202 4adac7df-926f-26a2-2b94-8c16560cd09d