perf data: Fix error return code in perf_data__create_dir()

Although 'ret' has been initialized to -1, but it will be reassigned by
the "ret = open(...)" statement in the for loop. So that, the value of
'ret' is unknown when asprintf() failed.

Reported-by: Hulk Robot <[e-mail]>
Signed-off-by: Zhen Lei <[e-mail]>
Acked-by: Jiri Olsa <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: http://lore.kernel.org/lkml/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/data.c

···
 int perf_data__create_dir(struct perf_data *data, int nr)
 {
 	struct perf_data_file *files = NULL;
-	int i, ret = -1;
+	int i, ret;
 
 	if (WARN_ON(!data->is_dir))
 		return -EINVAL;
···
 	for (i = 0; i < nr; i++) {
 		struct perf_data_file *file = &files[i];
 
-		if (asprintf(&file->path, "%s/data.%d", data->path, i) < 0)
+		ret = asprintf(&file->path, "%s/data.%d", data->path, i);
+		if (ret < 0)
 			goto out_err;
 
 		ret = open(file->path, O_RDWR|O_CREAT|O_TRUNC, S_IRUSR|S_IWUSR);