change type tether to usb

dump.py

@@ -53,7 +53,7 @@ def get_usb_iphone():
 
     device = None
     while device is None:
-        devices = [dev for dev in device_manager.enumerate_devices() if dev.type == 'tether']
+        devices = [dev for dev in device_manager.enumerate_devices() if dev.type == 'usb']
         if len(devices) == 0:
             print 'Waiting for USB device...'
             changed.wait()
@@ -328,4 +328,4 @@ if __name__ == '__main__':
     if os.path.exists(PAYLOAD_PATH):
         shutil.rmtree(PAYLOAD_PATH)
 
-    sys.exit(exit_code)
+    sys.exit(exit_code)