Disable SSH X11 forwarding for node

Even though X11 forwarding was probably useless anyway, disable it
just so it doesn't appear.

Change-Id: Iaaf7aece631c5dcd3d526a54f22b923048944499
Bug-Url:https://bugzilla.redhat.com/show_bug.cgi?id=1057177
Signed-off-by: Ryan Barry <rbarry@redhat.com>