Fix failure detection: ret is never 0

tests/errorcheck/workers_cpuid.c

@@ -195,7 +195,7 @@ int main(int argc, char **argv)
 			init_array(cpuids, nhwpus);
 			generate_arrangement(i, cpuids, nhwpus);
 			ret = test_combination(cpuids, i);
-			if (!ret)
+			if (ret != 1)
 			{
 				free(cpuids);
 				hwloc_topology_destroy(topology);