Reverts r14115 in trunk.

git-svn-id: http://svn.redmine.org/redmine/trunk@14117 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/setting.rb

@@ -243,7 +243,7 @@ END_SRC
 private
 
   def force_utf8_strings(arg)
-    if arg.is_a?(String) && arg.respond_to?(:force_encoding)
+    if arg.is_a?(String)
       arg.dup.force_encoding('UTF-8')
     elsif arg.is_a?(Array)
       arg.map do |a|