really fix the cmdweb test

this test to include the CmdStager module, not the CmdStagerVbs class

Before:
```
msf > loadpath test/modules
Loaded 32 modules:
    8 posts
    12 auxiliarys
    12 exploits
```

After:
```
msf > loadpath test/modules
Loaded 33 modules:
    8 posts
    12 auxiliarys
    13 exploits
msf > use exploit/test/cmdweb
msf exploit(cmdweb) > info

       Name: Command Stager Web Test
     Module: exploit/test/cmdweb
   Platform: Windows
 Privileged: Yes
    License: Metasploit Framework License (BSD)
       Rank: Manual
  Disclosed: 2010-02-03

Provided by:
  bannedit <bannedit@metasploit.com>

Available targets:
  Id  Name
  --  ----
  0   Automatic Targeting

Basic options:
  Name     Current Setting  Required  Description
  ----     ---------------  --------  -----------
  Proxies                   no        A proxy chain of format type:host:port[,type:host:port][...]
  RHOST                     yes       The target address
  RPORT    8080             yes       The target port
  VHOST                     no        HTTP server virtual host

Payload information:

Description:
  This module tests the command stager mixin against a shell.jsp
  application installed on an Apache Tomcat server.

msf exploit(cmdweb) > set RHOST 127.0.0.1
RHOST => 127.0.0.1
msf exploit(cmdweb) > run

[*] Started reverse handler on 127.0.0.1:4444
[*] Command Stager progress -   2.01% done (2046/101881 bytes)
[*] Command Stager progress -   4.02% done (4092/101881 bytes)
[*] Command Stager progress -   6.02% done (6138/101881 bytes)
[*] Command Stager progress -   8.03% done (8184/101881 bytes)
[*] Command Stager progress -  10.04% done (10230/101881 bytes)
[*] Command Stager progress -  12.05% done (12276/101881 bytes)
[*] Command Stager progress -  14.06% done (14322/101881 bytes)
[*] Command Stager progress -  16.07% done (16368/101881 bytes)
[*] Command Stager progress -  18.07% done (18414/101881 bytes)
...
```

test/modules/exploits/test/cmdweb.rb

@@ -10,7 +10,7 @@ class Metasploit3 < Msf::Exploit::Remote
   # =( need more targets and perhaps more OS specific return values OS specific would be preferred
 
   include Msf::Exploit::Remote::HttpClient
-  include Rex::Exploitation::CmdStagerVBS
+  include Msf::Exploit::CmdStager
 
   def initialize(info = {})
     super(update_info(info,