Remove scp option for gpu build

openstack-gpu/nodeimage.pkr.hcl

@@ -28,7 +28,6 @@ build {
     ]
     roles_path = "./ansible/roles"
     extra_arguments = [
-      "--scp-extra-args", "'-O'",
       "--extra-vars", "root_ssh_key='${var.root_ssh_key}'"
     ]
   }