Add ranger-tempest-plugin to blacklist

This commit adds ranger-tempest-plugin to the blacklist. The plugin
looks like very new and it looks it doesn't work correctly yet. So, it
might be better to skip to sanity for the plugin now.

Change-Id: I6d5d647d92916e5b62e8c67094d04f028e25ee67
diff --git a/tools/generate-tempest-plugins-list.py b/tools/generate-tempest-plugins-list.py
index c18f109..f1003a0 100644
--- a/tools/generate-tempest-plugins-list.py
+++ b/tools/generate-tempest-plugins-list.py
@@ -56,6 +56,7 @@
     # https://review.opendev.org/#/c/637718/
     'openstack/neutron-vpnaas',  # https://review.opendev.org/#/c/637719/
     'x/valet',  # https://review.opendev.org/#/c/638339/
+    'x/ranger-tempest-plugin',  # It looks this doesn't work correctly yet.
 ]
 
 url = 'https://review.opendev.org/projects/'