remove join table rows before removing owner row for habtm associations, fixes#5674

activerecord/lib/active_record/associations.rb

@@ -1416,8 +1416,8 @@ def has_and_belongs_to_many(association_id, options = {}, &extension)
         include Module.new {
           class_eval <<-RUBY, __FILE__, __LINE__ + 1
             def destroy                     # def destroy
-              super                         #   super
               #{reflection.name}.clear      #   posts.clear
+              super                         #   super
             end                             # end
           RUBY
         }

activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb

@@ -425,7 +425,7 @@ def test_deleting_all
   def test_removing_associations_on_destroy
     david = DeveloperWithBeforeDestroyRaise.find(1)
     assert !david.projects.empty?
-    assert_nothing_raised { david.destroy }
+    assert_raise(RuntimeError) { david.destroy }
     assert david.projects.empty?
     assert DeveloperWithBeforeDestroyRaise.connection.select_all("SELECT * FROM developers_projects WHERE developer_id = 1").empty?
   end