fix(tests): expect 502 for cloned app without deploy

The apps:clone --skip-deploy test expected 404 for the cloned app's
domain. With the new empty nginx config, undeployed apps now correctly
return 502 Bad Gateway instead of falling through to nginx's default.

tests/unit/apps_2.bats

@@ -166,7 +166,7 @@ teardown() {
   assert_success
   assert_output "http://$TEST_APP.$DOKKU_DOMAIN"
   assert_http_localhost_response "http" "$TEST_APP.$DOKKU_DOMAIN" "80" "/hello"
-  assert_http_localhost_response "http" "great-test-name.dokku.me" "80" "/hello" "" "404"
+  assert_http_localhost_response "http" "great-test-name.dokku.me" "80" "/hello" "" "502"
   run /bin/bash -c "dokku --force apps:destroy great-test-name"
   echo "output: $output"
   echo "status: $status"