main/nginx: enable mod-http-lua on s390x
luajit was just enabled on s390x, allowing mod-http-lua to be built thereon as well. This is used by the Kubernetes 'echoserver' E2E test image.
luajit was just enabled on s390x, allowing mod-http-lua to be built thereon as well. This is used by the Kubernetes 'echoserver' E2E test image.