Content items not indexed by legacySearchEngine

Steps to reproduce:

1. Install a master version without legacy;

2. Import the attached bundle and register it on EzPublishKernel.php and on routing.yml;

3. With the bundle working, from the ezpublish root, run the following command:

php ezpublish/console test:testSearch footer

You should get:

Found: footer
Execution terminated.

4. Now, via platformUI, create a folder "folder" and on its short name, for instance write "footer" as well;

5. From the ezpublish root, run the following command again:

php ezpublish/console test:testSearch footer

You still get only the default footer:

Found: footer
Execution terminated.

even if "footer" is contained in a field of "folder";

6. Run the following command:

php ezpublish/console test:testSearch folder

You'll get empty results:

Execution terminated.

doesn't find either by its name.