cifs: fix potential null pointer use in destroy_workqueue in init_cifs error path

In the Linux kernel, the following vulnerability has been resolved: cifs: fix potential null pointer use in destroy_workqueue in init_cifs error path Dan Carpenter reported a Smack static checker warning: fs/smb/client/cifsfs.c:1981 init_cifs() error: we previously assumed 'serverclose_wq' could be null (see line 1895) The patch which introduced the serverclose workqueue used the wrong oredering in error paths in init_cifs() for freeing it on errors.