dilate/connector: trap the right errors

If we had multiple potential connections, the act of cancelling the losing
ones was putting an error into log.err(), which flunked the tests. This
happened to appear on windows because the appveyor environment has different
interfaces than travis hosts.

src/wormhole/_dilation/connector.py

@@ -6,10 +6,11 @@ from attr.validators import instance_of, provides, optional
 from automat import MethodicalMachine
 from zope.interface import implementer
 from twisted.internet.task import deferLater
-from twisted.internet.defer import DeferredList
+from twisted.internet.defer import DeferredList, CancelledError
 from twisted.internet.endpoints import serverFromString
 from twisted.internet.protocol import ClientFactory, ServerFactory
 from twisted.internet.address import HostnameAddress, IPv4Address, IPv6Address
+from twisted.internet.error import ConnectingCancelledError
 from twisted.python import log
 from .. import ipaddrs  # TODO: move into _dilation/
 from .._interfaces import IDilationConnector, IDilationManager
@@ -308,6 +309,8 @@ class Connector(object):
         desc = describe_hint_obj(h, is_relay, self._tor)
         d = deferLater(self._reactor, delay,
                        self._connect, ep, desc, is_relay)
+        d.addErrback(lambda f: f.trap(ConnectingCancelledError,
+                                      CancelledError))
         d.addErrback(log.err)
         self._pending_connectors.add(d)