Revert "Implement GetState() for channel's connectivity check state."

This reverts commit ff72f9e692d0918b32646dadaf382aa4355d8437.

TBR=pthatcher@webrtc.org

BUG=

Review URL: https://webrtc-codereview.appspot.com/33469004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7805 4adac7df-926f-26a2-2b94-8c16560cd09d