normalize.rb: explicit separator

* lib/unicode_normalize/normalize.rb (canonical_ordering_one):
  use explicit separator, not to depend on $,.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48308 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/unicode_normalize/normalize.rb

@@ -79,7 +79,7 @@ module UnicodeNormalize
         end
       end
     end
-    return sorting.collect(&:first).join
+    return sorting.collect(&:first).join('')
   end
 
   ## Normalization Forms for Patterns (not whole Strings)