Update the test case so that it fails if the 404 view is missing the display_exceptions variable when we want to display exceptions.
Set the display_exceptions variable on the 404 view if we want to display exceptions.
Merge branch 'hotfix/3473'

Close #3473
Merge branch 'zfskeleton-issue155' of git://github.com/androa/zf2 into hotfix/3477
Merge branch 'hotfix/3477' into develop

Forward port #3477