core: NPE when adding detached disk without SD

Disk Profiles should be checked after verifying SD.

Change-Id: I81e8a487cae33c772b18addc94926babbfe19073
Bug-Url: https://bugzilla.redhat.com/1168525
Signed-off-by: Gilad Chaplik <gchaplik@redhat.com>
(cherry picked from commit 314ca8d1569aab865af9f8f236f723fc3744b395)