Fixed ftp.rb to get files larger than 16384

Existing ftp.rb did get_once, which limits file
DL to 16384 (def_block_size). Change to get and
added one more timeout variable see:
http://www.rubydoc.info/gems/librex/Rex%2FIO%2FStream:def_block_size
and
http://www.rubydoc.info/gems/librex/Rex%2FIO%2FStream:get_once
and
http://www.rubydoc.info/gems/librex/Rex%2FIO%2FStream:get

Author: bigendiansmalls

lib/msf/core/exploit/ftp.rb

@@ -213,7 +213,7 @@ def send_cmd_data(args, data, mode = 'a', nsock = self.sock)
     if (type == "get")
       # failed listings just disconnect..
       begin
-        data = self.datasocket.get_once(-1, ftp_timeout)
+        data = datasocket.get(ftp_timeout, ftp_data_timeout)
       rescue ::EOFError
         data = nil
       end
@@ -335,6 +335,13 @@ def ftp_timeout
     (datastore['FTPTimeout'] || 10).to_i
   end
 
+  #
+  # Returns the number of seconds to wait to get more FTP data
+  #
+  def ftp_data_timeout
+    (datastore['FTPDataTimeout'] || 1).to_i
+  end
+
 protected
 
   #