Disable WebRTC logging browser test.

The logging API has been moved to an extension API. This test is to be moved to extension tests.

Meanwhile, disabling fixes break on Chromium WebRTC bots.

R=xians@chromium.org

Review URL: https://codereview.chromium.org/25559005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226965 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226965