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