`@ set-colors` command fails if `cursor_text_color` not passed in 0.17.0

[CD3]

I installed 0.17.0 today and get an error when changing colors with the @set-colors command.

hamilton(:|✔) % kitty @ set-colors foreground=green                                                               ~/.config/kitty
Traceback (most recent call last):
  File "python3.7/runpy.py", line 280, in run_path
  File "python3.7/runpy.py", line 85, in _run_code
  File "kitty/__main__.py", line 121, in <module>
  File "kitty/__main__.py", line 117, in main
  File "kitty/__main__.py", line 23, in remote_control
  File "kitty/remote_control.py", line 173, in main
  File "kitty/set_colors.py", line 72, in message_to_kitty
KeyError: 'cursor_text_color'

The same error occurs if a config file that does not have cursor_text_color in it is used. If cursor_text_color is in the file, there is no error. In both cases, explicitly setting cursor_text_color at the command line works.

hamilton(:|✔) % kitty @ set-colors cursor_text_color=background foreground=green
hamilton(:|✔) % kitty @ set-colors cursor_text_color=background MyColors.conf