Move remaining current_savepoint_name to savepoints module

activerecord/lib/active_record/connection_adapters/abstract/savepoints.rb

 module ActiveRecord
   module ConnectionAdapters
     module Savepoints
+      def current_savepoint_name
+        current_transaction.savepoint_name
+      end
+
       def create_savepoint(name = current_savepoint_name)
         execute("SAVEPOINT #{name}")
       end

activerecord/lib/active_record/connection_adapters/abstract_adapter.rb

@@ -431,10 +431,6 @@ def can_perform_case_insensitive_comparison_for?(column)
       end
       private :can_perform_case_insensitive_comparison_for?
 
-      def current_savepoint_name
-        current_transaction.savepoint_name
-      end
-
       # Check the connection back in to the connection pool
       def close
         pool.checkin self