Importing ansible roles shows: "No changes in roles detected"

Issue

Importing ansible roles through WebUI or hammer shows the following message:

No changes in roles detected

If the roles_path value is defined in /etc/ansible/ansible.cfg, no ansible roles will be found.

Eg.:

[root@recife ~]# grep ^roles_path /etc/ansible/ansible.cfg 
roles_path    = /root/git/ansible/roles

[root@recife ansible]# hammer ansible roles import --location Montreal --organization ACME --proxy-id 1 --role-names role4
    Result: 
      No changes in ansible roles detected