default.mspec: end of options

* spec/default.mspec (MSpecScript): add the end of options to
  runruby.rb, to fix failure at ruby/spec@a0e55db.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56682 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

spec/default.mspec

@@ -21,5 +21,6 @@ class MSpecScript
     -I#{srcdir}
     -I#{srcdir}/#{config['EXTOUT']}/common
     #{srcdir}/tool/runruby.rb --archdir=#{Dir.pwd} --extout=#{config['EXTOUT']}
+    --
   ]
 end