More cleanups

Signed-off-by: Mario Danic <mario@lovelyhq.com>

app/src/main/java/com/nextcloud/talk/activities/CallActivity.java

@@ -1009,6 +1009,12 @@ public class CallActivity extends AppCompatActivity {
                 peerConnectionFactory = null;
             }
 
+            localMediaStream.removeTrack(localAudioTrack);
+            localMediaStream.removeTrack(localVideoTrack);
+            localMediaStream = null;
+            localAudioTrack = null;
+            localVideoTrack = null;
+
             hangupNetworkCalls();
         }
     }

app/src/main/java/com/nextcloud/talk/webrtc/MagicPeerConnectionWrapper.java

@@ -99,6 +99,7 @@ public class MagicPeerConnectionWrapper {
         }
 
         if (peerConnection != null) {
+            peerConnection.removeStream(localMediaStream);
             peerConnection.close();
             peerConnection = null;
         }