remove reference to Test::Unit

Author: tenderlove

Diff for: railties/lib/rails/console/app.rb

@@ -3,7 +3,6 @@
 require 'action_controller'
 
 # work around the at_exit hook in test/unit, which kills IRB
-Test::Unit.run = true if Test::Unit.respond_to?(:run=)
 
 module Rails
   module ConsoleMethods