Fix the behavior of `C-w C-c`

[rettakjak]

Here's another small PR, this time to fix an inconsistency I've noticed with respect to Vim behavior.

In Evil C-w C-c has been closing the current window. This behavior appears to have been silently introduced in commit ec53465dafc99357161dffc53d49592914d628e5.

Vim, however, doesn't close the window in this case. From the Vim documentation:

You might have expected that CTRL-W CTRL-C closes the current window, but that does not work, because the CTRL-C cancels the command.

Now use ignore instead of evil-window-delete so nothing happens in this case (specifically, we do keep it defined so we don't get the message "C-w C-c is undefined").

Thanks!