"ssh-keygen -R hostname" errors out with non-existent known_hosts

[Nico Kadel-Garcia]

I've just run into what I consider a bug: If ~/.ssh/known_hosts does
not exist, and the account owner runs the command or their script
includes the command "ssh-keygen -R {hostname}", it reports an error
rather than reporting "oh, yes, the file was empty and therefore your
attempt to delete the hostname was unnecessary".

If I want to delete a hostkey entry, and there is none to be found,
shouldn't that be considered a successful operation?