Fix regex for meta directories

There are other files like os_tripleo_baremetal_node_introspection.py,
that contains "meta" in the name that makes zuul skip jobs.

Change-Id: Ib995f4862bb59428f9e5ceb6b17fbc8b5c352213

zuul.d/layout.yaml

@@ -45,7 +45,7 @@
           - ^tox.ini$
           - ^tripleo_ansible/playbooks/docker-vfs-setup.yml$
           - ^tripleo_ansible/.*molecule.*
-          - ^tripleo_ansible/.*meta.*
+          - ^tripleo_ansible/roles/.*/meta.*
           - ^tripleo_ansible/roles/test_deps/.*
           - ^zuul.d/.*
       - tripleo-ci-centos-8-standalone: &basic_standalone