API spec allows this, for example [Deleting a directory](https://github.com/coreos/etcd/blob/master/Documentation/api.md#deleting-a-directory)

in store/v2/delete_command.go there is
```
func (c *DeleteCommand) Apply(context raft.Context) (interface{}, error) {
	...
	if c.Recursive {
		// recursive implies dir
		c.Dir = true
	}
	...
}
```
so I believe that it's OK.