Stringify the attribute value before #force_enconding (#21453).

git-svn-id: http://svn.redmine.org/redmine/trunk@15025 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/auth_source_ldap.rb

@@ -198,7 +198,7 @@ class AuthSourceLdap < AuthSource
   def self.get_attr(entry, attr_name)
     if !attr_name.blank?
       value = entry[attr_name].is_a?(Array) ? entry[attr_name].first : entry[attr_name]
-      value.force_encoding('UTF-8')
+      value.to_s.force_encoding('UTF-8')
     end
   end
 end