tests: remove duplicated test case in networkxml2firewalltest

Reviewed-by: NLaine Stump <laine@laine.org>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

tests/networkxml2firewalltest.c

@@ -154,7 +154,6 @@ mymain(void)
     DO_TEST("nat-no-dhcp");
     DO_TEST("nat-ipv6");
     DO_TEST("route-default");
-    DO_TEST("route-default");
 
  cleanup:
     return ret == 0 ? EXIT_SUCCESS : EXIT_FAILURE;