[net] Disable Async DNS field trial

Disabling due to http://crbug.com/121085

NOTRY=true
BUG=143454


Review URL: https://chromiumcodereview.appspot.com/10894041

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@154369 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed