Trezor: fixes for latest libtrezor

We were relying on internals of libtrezor that they just
changed.  However their changes don't work on Mac either.
Work around both issues.  I think this...

Fixes #1637

lib/plugins.py

@@ -227,7 +227,7 @@ class BasePlugin(PrintError):
     def settings_dialog(self):
         pass
 
-Device = namedtuple("Device", "path id_ product_key")
+Device = namedtuple("Device", "path interface_number id_ product_key")
 DeviceInfo = namedtuple("DeviceInfo", "device description initialized")
 
 class DeviceMgr(PrintError):
@@ -423,8 +423,8 @@ class DeviceMgr(PrintError):
         for d in hid.enumerate(0, 0):
             product_key = (d['vendor_id'], d['product_id'])
             if product_key in self.recognised_hardware:
-                devices.append(Device(d['path'], d['serial_number'],
-                                      product_key))
+                devices.append(Device(d['path'], d['interface_number'],
+                                      d['serial_number'], product_key))
 
         # Now find out what was disconnected
         pairs = [(dev.path, dev.id_) for dev in devices]

plugins/trezor/plugin.py

@@ -209,16 +209,18 @@ class TrezorCompatiblePlugin(BasePlugin, ThreadJob):
                 wallet.last_operation = self.prevent_timeout
 
     def create_client(self, device, handler):
-        path = device.path
-        pair = ((None, path) if self.HidTransport._detect_debuglink(path)
-                else (path, None))
+        if device.interface_number == 1:
+            pair = [None, device.path]
+        else:
+            pair = [device.path, None]
+
         try:
             transport = self.HidTransport(pair)
         except BaseException as e:
             # We were probably just disconnected; never mind
-            self.print_error("cannot connect at", path, str(e))
+            self.print_error("cannot connect at", device.path, str(e))
             return None
-        self.print_error("connected to device at", path)
+        self.print_error("connected to device at", device.path)
 
         client = self.client_class(transport, handler, self)