Disable WEBRTC_SVNREVISION

Description:
This CL will temporally define WEBRTC_SVNREVISION as "n/a" because it
could break Chromium if svn is not installed.
The long term solution is a have a script that could deal with it, and
have it support git-svn which is used by most developers.

BUG=496
TEST=build on Linux
Review URL: https://webrtc-codereview.appspot.com/569007

git-svn-id: http://webrtc.googlecode.com/svn/trunk@2187 4adac7df-926f-26a2-2b94-8c16560cd09d
1 file changed