Mark ErrorPageTest.IFrameDNSError_GoBackAndForward as flaky since it failed on Linux.
Mark ErrorPageTest.IFrameDNSError_GoBackAndForward as flaky since it failed
on Linux.

BUG=19361

Review URL: http://codereview.chromium.org/384050

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@31689 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser