only _run_commit_callbacks when destroyed or persisted:

should fix issues with commit callbacks getting called when the record
is not persisted (yet) in a inner transaction or due to some other edge
case.

see also caabed6c76

Conflicts:
	activerecord/lib/active_record/transactions.rb

activerecord/lib/active_record/transactions.rb

@@ -278,7 +278,7 @@ module ActiveRecord
 
     # Call the after_commit callbacks
     def committed! #:nodoc:
-      run_callbacks :commit
+      run_callbacks :commit if destroyed? || persisted?
     ensure
       @_start_transaction_state.clear
     end