UX: notify download of answer file status

Notify successfull download of answer file.
Better handling of the notify of failure when
the password is provided by the answer file.

Bug-Url: https://bugzilla.redhat.com/1007422
Change-Id: I2ed7fae0ee808b9d7e59409fae0f7e4edbb9bf92
Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>