Tested on Ubuntu 16.04, Elasticsearch/X-pack 6.2.0 and 6.2.1, puppet module elastic-elasticsearch v6.2.0.
6.2.0 included this merge regarding meta-plugins. When installing x-pack (a meta-plugin) via puppet, a file called '.name' is created in the root x-pack plugin directory (see here). Since this '.name' file is not a valid plugin directory, an error  is raised during Elasticsearch startup.
Adding an additional check here in PluginInfo.extractAllPlugins to exclude .name files.
Individual plugins (like ingest-attachment) do not seem to be impacted. Deleting the .name file will allow Elasticsearch to start.
- install elasticsearch via official puppet module
- install x-pack via puppet module
: org.elasticsearch.bootstrap.StartupException: org.elasticsearch.bootstrap.BootstrapException: java.nio.file.FileSystemException: /usr/share/elasticsearch/plugins/x-pack/.name/plugin-descriptor.properties: Not a directory