import-certs.sh: simplify expiry check
import-certs.sh: simplify expiry check

erdgeist/letsencrypt.sh,Vitexus/dehydrated,ahnooie/dehydrated,lukas2511/dehydrated,erdgeist/letsencrypt.sh,erorus/letsencrypt.sh,Rayne/letsencrypt.sh,lukas2511/letsencrypt.sh,dennisschuerholz/dehydrated