Fix for state warning in ansible 2.6.5

[Spreadcat]

This change fixes the warning in ansible 2.6.5 regarding the state parameter in the module file.

TASK [ansible_role_logrotate : Symlink for hourly rotation] ********************
 [WARNING]: The src option requires state to be 'link' or 'hard'.  This will
become an error in Ansible 2.10

[hadret]

This approach won't fly -- logrotate_use_hourly_rotation is a boolean and it's always defined in defaults/main.yml. It will result in always creating link, regardless of the boolean value. I think this approach would be better:

- name: Symlink for hourly rotation
  file:
    path: "/etc/cron.hourly/logrotate"
    src: "/etc/cron.daily/logrotate"
    state: link
  when: logrotate_use_hourly_rotation | bool

The caveat with this approach is the change of the behavior -- the symlink won't be cleaned up/removed on the logrotate_use_hourly_rotation change.