File CVE-2016-0753.patch of Package rubygem-activesupport-4_2

diff --git a/activesupport/lib/active_support/callbacks.rb b/activesupport/lib/active_support/callbacks.rb
index 355cedb..98fd6b5 100644
--- a/activesupport/lib/active_support/callbacks.rb
+++ b/activesupport/lib/active_support/callbacks.rb
@@ -770,7 +770,7 @@ module ActiveSupport
         options = names.extract_options!
 
         names.each do |name|
-          class_attribute "_#{name}_callbacks"
+          class_attribute "_#{name}_callbacks", instance_writer: false
           set_callbacks name, CallbackChain.new(name, options)
 
           module_eval <<-RUBY, __FILE__, __LINE__ + 1
-- 
2.2.1