fix(docker): pass registry-failure up

lib/datasource/docker/index.js

@@ -419,6 +419,9 @@ async function getLabels(registry, repository, tag) {
     await renovateCache.set(cacheNamespace, cacheKey, labels, cacheMinutes);
     return labels;
   } catch (err) {
+    if (err.message === 'registry-failure') {
+      throw err;
+    }
     if (err.statusCode === 401) {
       logger.info(
         { registry, dockerRepository: repository },