AppRTCDemo(android): close() the throw-away DataChannel.

Otherwise, the PeerConnection remembers the channel enough to include an
m=application line in its offer SDP, causing connection to chrome to fail, since
apprtc.appspot.com doesn't include an RtpDataChannels:true constraint in its
RTCPeerConnection constructor call.

R=wu@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/6729005

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5354 4adac7df-926f-26a2-2b94-8c16560cd09d

talk/examples/android/src/org/appspot/apprtc/AppRTCDemoActivity.java

@@ -178,6 +178,7 @@ public class AppRTCDemoActivity extends Activity
       PeerConnection pc) {
     DataChannel dc = pc.createDataChannel("dcLabel", new DataChannel.Init());
     abortUnless("dcLabel".equals(dc.label()), "WTF?");
+    dc.close();
     dc.dispose();
   }