core:Use audit log on disk finish action

Direct lun disk should only log it finished the action, since there is no
use of tasks in the process.
We also should log when remove disk ends for all type of disks.

Change-Id: I22b145fbc12481e40eaa8329eb8ce35f7c39a320
Bug-Url: https://bugzilla.redhat.com/910693
Signed-off-by: Maor Lipchuk <mlipchuk@redhat.com>