Use non-existent channel to default ctest to use own image in update testing.

BUG=chromium-os:19471
TEST=Unittest + ctest by itself to see image used correctly

Change-Id: I713f09aa2a5d90e3ef8d8dca3c59d4821d10c79d
Reviewed-on: http://gerrit.chromium.org/gerrit/6445
Tested-by: Chris Sosa <sosa@chromium.org>
Reviewed-by: Don Garrett <dgarrett@chromium.org>
1 file changed