Revert "Restore ptypes.txt file"

This reverts r6460. It turns out the file was no longer needed after
all.

BUG=2996
TBR=tina.legrand@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/12769004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6478 4adac7df-926f-26a2-2b94-8c16560cd09d