Fixes "argument list too long" problem on Linux by using the "find" command instead of re-implementing one in python. R=pbos@webrtc.org TBR=andrew@webrtc.org BUG=b/15773179 Review URL: https://webrtc-codereview.appspot.com/18929004 git-svn-id: http://webrtc.googlecode.com/svn/trunk@6782 4adac7df-926f-26a2-2b94-8c16560cd09d