ada-mode: remove ada-mode-keys.el
ada-mode: remove ada-mode-keys.el

It's not a versioned URL so that SHA is changing.

Closes #372.

Signed-off-by: Alex Dunn <46952c1342d5ce1a4f5689855eda3c9064bca8f6@gmail.com>

Homebrew/homebrew-emacs