profiles: ad: authz: properly fail if upn cannot be found

Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1151127
Change-Id: I78f7f426f01016bd54e29467d96d8b46d94197b7
Signed-off-by: Alon Bar-Lev <alonbl@redhat.com>