Respond with 404 instead of 500 when revision/entry is not found in the repository (#7307).

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@4710 e93f8b46-1217-0410-a6f0-8f06a7374b81

test/functional/repositories_mercurial_controller_test.rb

@@ -201,7 +201,7 @@ class RepositoriesMercurialControllerTest < ActionController::TestCase
       @repository.reload
       ['', ' ', nil].each do |r|
         get :revision, :id => 1, :rev => r
-        assert_response 500
+        assert_response 404
         assert_error_tag :content => /was not found/
       end
     end