virNetDevSetVfMac: Fix error message on invalid args

If virNetDevSetVfMac() is called with either @macaddr or
@allowRetry arguments NULL an error is reported, because this is
considered invalid use. However, the error message is not
informative as it could be.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

src/util/virnetdev.c

@@ -1642,7 +1642,9 @@ virNetDevSetVfMac(const char *ifname, int vf,
     };
 
     if (macaddr == NULL || allowRetry == NULL) {
-        virReportError(EINVAL, "%s", _("Invalid parameters: %d"));
+        virReportError(EINVAL,
+                       _("Invalid parameters macaddr=%p allowRetry=%p"),
+                       macaddr, allowRetry);
         return -EINVAL;
     }