bpftool: Fix JSON writer resource leak in version command

When using `bpftool --version -j/-p`, the JSON writer object
created in do_version() was not properly destroyed after use.
This caused a memory leak each time the version command was
executed with JSON output.

Fix: 004b45c (tools: bpftool: provide JSON output for all possible commands)
Signed-off-by: Yuan Chen <[email protected]>
Suggested-by: Quentin Monnet <[email protected]>

Author: chenyuan0001

tools/bpf/bpftool/main.c

@@ -533,8 +533,12 @@ int main(int argc, char **argv)
 	if (argc < 0)
 		usage();
 
-	if (version_requested)
-		return do_version(argc, argv);
+	if (version_requested) {
+		ret = do_version(argc, argv);
+		if (json_output)
+			jsonw_destroy(&json_wtr);
+		return ret;
+	}
 
 	ret = cmd_select(commands, argc, argv, do_help);