Remove metrics_unittests

This target has been merged into video_engine_tests in r5284.

BUG=webrtc:1843
R=pbos@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/6129004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@5319 4adac7df-926f-26a2-2b94-8c16560cd09d
4 files changed