Mark version_negotiation_test as flaky.
Mark version_negotiation_test as flaky.

BUG=
R=kustermann@google.com

Review URL: https://codereview.chromium.org//32823019

git-svn-id: a962b240025cf0577aa172e20f49ccb159ba6be1@29091 260f80e4-7a28-3924-810f-c04153c831b5

maxwellpeterson-wf/pub,computmaxer/pub,dart-lang/pub,cjkao/dart-pub,dart-lang/pub