storage: Fix error retval for getDeviceType

On error from virAsprintf we would erroneously return 0 with
the @*type not being set. Change to a return -1 on error like
we should have been doing.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

src/storage/storage_util.c

@@ -4044,8 +4044,10 @@ getDeviceType(uint32_t host,
     int retval = 0;
 
     if (virAsprintf(&type_path, "/sys/bus/scsi/devices/%u:%u:%u:%u/type",
-                    host, bus, target, lun) < 0)
+                    host, bus, target, lun) < 0) {
+        retval = -1;
         goto out;
+    }
 
     typefile = fopen(type_path, "r");
     if (typefile == NULL) {