host: remove empty virtualzation check.

related to #547
There is an architecture which supports no virtualization.

host/host_test.go

@@ -133,9 +133,6 @@ func TestVirtualization(t *testing.T) {
 	if err != nil {
 		t.Errorf("Virtualization() failed, %v", err)
 	}
-	if system == "" || role == "" {
-		t.Errorf("Virtualization() retuns empty system or role:  %s, %s", system, role)
-	}
 
 	t.Logf("Virtualization(): %s, %s", system, role)
 }