Update run.sh

On the first run, this script shows the error 'diff: can't stat '/output/cert.pem': No such file or directory', because the file does not exist in the folder `/output` yet. This bugfix ensures, that the diff is only called, when all required files are available.

optional/traefik-certdumper/run.sh

@@ -5,8 +5,10 @@ function dump() {
 
     traefik-certs-dumper file --crt-name "cert" --crt-ext ".pem" --key-name "key" --key-ext ".pem" --domain-subdir --dest /tmp/work --source /traefik/acme.json > /dev/null
 
-    if diff -q /tmp/work/${DOMAIN}/cert.pem /output/cert.pem >/dev/null && \
-	    diff -q /tmp/work/${DOMAIN}/key.pem /output/key.pem >/dev/null ; then
+    if [[ -f /tmp/work/${DOMAIN}/cert.pem && -f /tmp/work/${DOMAIN}/key.pem && -f /output/cert.pem && -f /output/key.pem ]] && \
+	diff -q /tmp/work/${DOMAIN}/cert.pem /output/cert.pem >/dev/null && \
+	diff -q /tmp/work/${DOMAIN}/key.pem /output/key.pem >/dev/null ; \
+    then
 	echo "$(date) Certificate and key still up to date, doing nothing"
     else
 	echo "$(date) Certificate or key differ, updating"