[PHP-FPM] Fix lookup of Postfix container when SQL applied an update

data/Dockerfiles/phpfpm/docker-entrypoint.sh

@@ -58,8 +58,8 @@ done
 
 # doing post-installation stuff, if SQL was upgraded (master and slave)
 if [ ${SQL_CHANGED} -eq 1 ]; then
-  POSTFIX=($(curl --silent --insecure https://dockerapi/containers/json | jq -r '.[] | {name: .Config.Labels["com.docker.compose.service"], project: .Config.Labels[\"com.docker.compose.project\"], id: .Id}' | jq -rc 'select( .name | tostring | contains("postfix-mailcow")) | select( .project | tostring | contains(\"${COMPOSE_PROJECT_NAME}\")) | .id' | tr "\n" " "))
-  if [[ -z ${POSTFIX} ]]; then
+  POSTFIX=$(curl --silent --insecure https://dockerapi/containers/json | jq -r ".[] | {name: .Config.Labels[\"com.docker.compose.service\"], project: .Config.Labels[\"com.docker.compose.project\"], id: .Id}" 2> /dev/null | jq -rc "select( .name | tostring | contains(\"postfix-mailcow\")) | select( .project | tostring | contains(\"${COMPOSE_PROJECT_NAME}\")) | .id" 2> /dev/null)
+  if [[ -z "${POSTFIX}" ]] || ! [[ "${POSTFIX}" =~ ^[[:alnum:]]*$ ]]; then
     echo "Could not determine Postfix container ID, skipping Postfix restart."
   else
     echo "Restarting Postfix"