error when replacing a certificate with ACME

[Geal]

I was updating sozu-acme to sozu 0.14 and encountered an issue with the new certificate resolver.

Apparently when sending a ReplaceCertificate message, I get the following error:

2021-September-22T08:01:08.658111Z 1632297668658111892 1997907 MAIN DEBUG       sozu::command   worker 0 replied message: ProxyResponse { id: "ID-rjFqWb-worker-0", status: Error("failed to handle certificate request, got a resolver error, certificate is still in use"), data: None }                                                                                                                     
2021-September-22T08:01:08.658355Z 1632297668658355391 1997907 MAIN DEBUG       sozu::command   worker 0 sent back ProxyResponse { id: "ID-rjFqWb-worker-0", status: Error("failed to handle certificate request, got a resolver error, certificate is still in use"), data: None }                                                                                                                            
2021-September-22T08:01:08.660449Z 1632297668660449250 1997907 MAIN DEBUG       sozu::command   removing client CL-0                 

Since the replace operation is currently done with a remove then add, it makes sense that an error would be returned, so replacing certificates should be implemented separately