Fix for GRAILS-10917

A small commit fixed during GGX 2013, regarding the model being passed in case of errors when using the respond keyword. 

I unignored the test class and ignored all the separated tests to allow the 2 tests I added to run. I think my tests don't cause issues on the build server since they don't test the contentType, which seems to fail on the build server as well as my machine (JDK issue?)