[Portfolio] Graceful failure when a resource isn't there

[Sean Keesler]

I have frequently found myself in front of a browser looking at links
to content that are not there (I've deleted them for testing).  This
happens when an evaluator deletes an evaluation, a student removes a
form instance or a reviewer deletes a piece of feedback and the
student still has on their screen the state of things the last time
they refreshed the page.

When I click on those links I get the 403 tomcat error that I know I
will, but I wonder if the system should be a bit smarter and display a
message that makes sense, like

"Oops! That piece of content isn't here any longer.
Someone must have deleted it while you were twiddling your thumbs!"

for a second and then take the student back to where they were, rather
than exposing the user that ugly bit.


Sean