require caller to provide transit relay too

src/wormhole/blocking/transit.py

@@ -2,7 +2,6 @@ from __future__ import print_function
 import re, time, threading, socket, SocketServer
 from binascii import hexlify, unhexlify
 from nacl.secret import SecretBox
-from .. import const
 from ..util import ipaddrs
 from ..util.hkdf import HKDF
 
@@ -270,8 +269,8 @@ class RecordPipe:
         self.skt.close()
 
 class Common:
-    def __init__(self, transit_relay=None):
-        self._transit_relay = transit_relay or const.TRANSIT_RELAY
+    def __init__(self, transit_relay):
+        self._transit_relay = transit_relay
         self.winning = threading.Event()
         self._negotiation_check_lock = threading.Lock()
         self._have_transit_key = threading.Condition()

src/wormhole/scripts/cmd_receive_file.py

@@ -8,7 +8,7 @@ APPID = "lothar.com/wormhole/file-xfer"
 
 def receive_file(args):
     # we're receiving
-    transit_receiver = TransitReceiver(transit_relay=args.transit_helper)
+    transit_receiver = TransitReceiver(args.transit_helper)
 
     r = Receiver(APPID, args.relay_url)
     code = args.code

src/wormhole/scripts/cmd_send_file.py

@@ -10,7 +10,7 @@ def send_file(args):
     # we're sending
     filename = args.filename
     assert os.path.isfile(filename)
-    transit_sender = TransitSender(transit_relay=args.transit_helper)
+    transit_sender = TransitSender(args.transit_helper)
 
     i = Initiator(APPID, args.relay_url)
     code = i.get_code(args.code_length)