do not return exit code 1 if domains.txt is empty, fixes #51
do not return exit code 1 if domains.txt is empty, fixes #51

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