backenduser and portal user with no permissions can access to file and folder !

[daas13]

          user with no permissions can access to file and folder !

Originally posted by @daas13 in #385 (comment)

[victoralmau]

Please add steps to reproduce the error in runbot and explain it well.

[kobros-tech]

Now the issue is solved in the same PR as I guess, you can review :)