Bug#888841: hopenpgp-tools: "hokey lint" should warn if a key is a subkey of itself

[Clint Adams]

On Tue, Jan 30, 2018 at 09:20:56AM -0500, Daniel Kahn Gillmor wrote:
> Discovered at
> https://github.com/open-keychain/open-keychain/issues/2260 is a
> bizarre construct, where a key is its own subkey.  I've attached it
> here.
> 
> hokey lint should notice this misconfiguration and warn about it
> explicitly.

Do we just care about "same fingerprint" or are there other factors
which matter?