zns: fix check for valid global context

When the code was switched to use nvme_scan_topology, the introduced
error check was incorrect.

Fixes: 7daa1e9 ("plugins: replace nvme_scan with nvme_scan_topology")
Signed-off-by: Daniel Wagner <[email protected]>

Author: igaw

plugins/zns/zns.c

@@ -107,7 +107,7 @@ static int list(int argc, char **argv, struct command *acmd,
 	struct table *t = table_init_with_columns(columns, ARRAY_SIZE(columns));
 
 	ctx = libnvme_create_global_ctx(stdout, DEFAULT_LOGLEVEL);
-	if (ctx) {
+	if (!ctx) {
 		fprintf(stderr, "Failed to create root object\n");
 		return -ENOMEM;
 	}