If a provided configuration value is the same as the default value, ignore it (fixes issue with "docker run ... bash" followed by "docker-entrypoint.sh rabbitmq-server" complaining about SSL environment variables not being set)

Author: tianon

docker-entrypoint.sh

@@ -65,6 +65,10 @@ for conf in "${allConfigKeys[@]}"; do
 	var="RABBITMQ_${conf^^}"
 	val="${!var:-}"
 	if [ "$val" ]; then
+		if [ "${configDefaults[$conf]:-}" ] && [ "${configDefaults[$conf]}" = "$val" ]; then
+			# if the value set is the same as the default, treat it as if it isn't set
+			continue
+		fi
 		haveConfig=1
 		case "$conf" in
 			ssl_*) haveSslConfig=1 ;;