Replace -> {} with a proc.

When `parse_options_for` was called for a command that
hadn't set up any option parsing with `options_for`, the `call` method
would be sent to `-> {}`, which didn't like to be passed two arguments.

Switch to `proc {}` which can accept several arguments.

railties/lib/rails/commands/command.rb

@@ -41,7 +41,7 @@ def exists?(task_name) # :nodoc:
         @@command_options = {}
 
         def parse_options_for(command_name)
-          @@command_options.fetch(command_name, -> {}).call(@option_parser, @options)
+          @@command_options.fetch(command_name, proc {}).call(@option_parser, @options)
         end
 
         def build_option_parser