Comment # 1 on bug 1185647 from Dario Faggioli

Not sure if it is related, but now the system is also showing this, during
reboot:

  May 05 11:54:02 localhost.localdomain systemd[1]: Unmounting /etc...
  May 05 11:54:02 localhost.localdomain systemd[1]: Stopping Security Auditing 
  Service...
  May 05 11:54:02 localhost.localdomain umount[2819]: umount: /etc: target is
busy.
  May 05 11:54:02 localhost.localdomain systemd[1]: etc.mount: Mount process 
  exited, code=exited, status=32/n/a
  May 05 11:54:02 localhost.localdomain systemd[1]: Failed unmounting /etc.