Correctly rebuild WebRTCDemo after jni/ source file changes

BUG=1980
TEST=Modify source file under jni/ and WebRTCDemo will rebuild
R=fischman@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/1831004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@4377 4adac7df-926f-26a2-2b94-8c16560cd09d
4 files changed