Improve path_surgery warning (#4293)
Improve path_surgery warning (#4293)

Stops output like:

Failed to find certbot.log in PATH: ...
renew-hook command certbot.log exists, but is not executable.
letsencrypt/letsencrypt,lmcro/letsencrypt,jsha/letsencrypt,lmcro/letsencrypt,stweil/letsencrypt,jsha/letsencrypt,letsencrypt/letsencrypt,stweil/letsencrypt