apps/nshlib:  Fix a copy paste error introduced in commit
@@ -160,7 +160,7 @@ int nsh_builtin(FAR struct nsh_vtbl_s *vtbl, FAR const char *cmd,
* waitpid() to return with ECHILD.
*/
- ret = waitpid(pid, &rc, WUNTRACED);
+ ret = waitpid(ret, &rc, WUNTRACED);
if (ret < 0)
{
/* If the child thread does not exist, waitpid() will return
