Disable a test in libjingle_peerconnection_unittest for DrMemory

BUG=3453
R=kjellander@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/12689004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6334 4adac7df-926f-26a2-2b94-8c16560cd09d