Change presubmit script to not allow uploads at all

Direct people to github

TBR=whesse@google.com

BUG=

Review URL: https://codereview.chromium.org//1130053006

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@45833 260f80e4-7a28-3924-810f-c04153c831b5
1 file changed
tree: 3e48a10e5df3e81469754695d0c94f02a5aa696f
  1. dart/
  2. deps/