.gitignore updates

Update after Chromium roll in https://review.webrtc.org/24179004/
and Android project updates in https://review.webrtc.org/25029004/

BUG=
TBR=phoglund@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/24239004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7665 4adac7df-926f-26a2-2b94-8c16560cd09d