Fix ansible_runner content seeding

The fetch_ansible_galaxy code, when called at run-time works correctly,
however, this method, meant for seeding galaxy roles at build time,
incorrectly looked at the root directory instead of the roles directory,
and so did nothing.

lib/vmdb/plugins.rb

@@ -55,7 +55,7 @@ def ansible_content
     def ansible_runner_content
       @ansible_runner_content ||= begin
         map do |engine|
-          content_dir = engine.root.join("content", "ansible_runner")
+          content_dir = engine.root.join("content", "ansible_runner", "roles")
           next unless File.exist?(content_dir.join("requirements.yml"))
 
           [engine, content_dir]