Fixed a nil method error in Setting#value=

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@3417 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/setting.rb

@@ -97,7 +97,7 @@ class Setting < ActiveRecord::Base
   end
   
   def value=(v)
-    v = v.to_yaml if v && @@available_settings[name]['serialized']
+    v = v.to_yaml if v && @@available_settings[name] && @@available_settings[name]['serialized']
     write_attribute(:value, v.to_s)
   end