change the default SMBDomain to .

Due to a recent change using WORKGROUP
as the SMBDomain causes Trust errors.
Using '.' instead works fine.

Author: David Maloney

lib/msf/core/exploit/smb/client/authenticated.rb

@@ -14,7 +14,7 @@ def initialize(info = {})
       [
         OptString.new('SMBUser', [ false, 'The username to authenticate as', '']),
         OptString.new('SMBPass', [ false, 'The password for the specified username', '']),
-        OptString.new('SMBDomain',  [ false, 'The Windows domain to use for authentication', 'WORKGROUP']),
+        OptString.new('SMBDomain',  [ false, 'The Windows domain to use for authentication', '.']),
       ], Msf::Exploit::Remote::SMB::Client::Authenticated)
   end
 end