Don't try to execute any non-executable file in LE postrenew dir.

roles/common/files/etc_cron-monthly_letsencrypt-renew

@@ -19,7 +19,7 @@ done
 service apache2 start
 
 # Services that rely on LE certificates may need restarted and/or other actions.
-for script in $(find /etc/letsencrypt/postrenew/ -maxdepth 1 -type f); do
+for script in $(find /etc/letsencrypt/postrenew/ -maxdepth 1 -type f -executable); do
   echo "Executing ${script}."
   $script
 done