This adds barback-0.14.0+3 to the suite of legacy barbacks that pub is tested
against.

BUG=18948
R=rnystrom@google.com

Review URL: https://codereview.chromium.org//310233002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@37199 260f80e4-7a28-3924-810f-c04153c831b5