Merge pull request #2185 from castlerock/lazy_load_abstract_adapter

lazy load ConnectionAdapters remove require.

activerecord/lib/active_record.rb

@@ -41,7 +41,8 @@ module ActiveRecord
   eager_autoload do
     autoload :ActiveRecordError, 'active_record/errors'
     autoload :ConnectionNotEstablished, 'active_record/errors'
-
+    autoload :ConnectionAdapters, 'active_record/connection_adapters/abstract_adapter'
+    
     autoload :Aggregations
     autoload :Associations
     autoload :AttributeMethods

activerecord/lib/active_record/base.rb

@@ -2166,6 +2166,4 @@ def clear_timestamp_attributes
   end
 end
 
-# TODO: Remove this and make it work with LAZY flag
-require 'active_record/connection_adapters/abstract_adapter'
 ActiveSupport.run_load_hooks(:active_record, ActiveRecord::Base)