Canvas security cases need to be updated due to server name change

Philip can you update your submitted and approved canvas tests?
I opened Bugzilla bug #12004 (http://www.w3.org/Bugs/Public/show_bug.cgi?id=12004) to track this change.

Basically the test2.w3.org servername is no longer valid and causes a few canvas security cases to fail.
The fix is to use the http://w3c-test.org/html/tests/approved/images/ for the image path for both the approved and submitted cases.

-Thx