GN: Remove webrtc_base target in favor for rtc_base.

The last reference to the old target name was
removed in https://crrev.com/7c9149860a8a0ca24350d2e80dbc280990a0cbb7

R=perkj@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/33079004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@8179 4adac7df-926f-26a2-2b94-8c16560cd09d
1 file changed