core: Finalizing step typo

Removed the full stop from "Finalizing." in order to match "Validating"
and "Executing" steps.

Change-Id: Icf9d4372f99e65d5b113aabcc87777beae85bed2
Bug-Url: https://bugzilla.redhat.com/1139311
Signed-off-by: Allon Mureinik <amureini@redhat.com>