Avoid input engine respond to the Superkey

[qiangzhao]

Avoid the input engine responding to the Superkey, otherwise, this will cause ibus-pinyin to not switch to other input engines under Wayland.

[qiangzhao]

Hi maintainers: @phuang
With full respect. the "super + space" key binding stop works after using the ibus-pinyin to input Chinese. Env is openSUSE with Wayland. Xwindows don't have this issue.
Thank you so much for taking your valuable time to take a review!

[epico]

Could you check whether the code in BopomofoEngine and PinyinEngine is necessary?

[qiangzhao]

Could you check whether the code in BopomofoEngine and PinyinEngine is necessary?

Yes, you are right. I have test and update the request.
Thank you very much.

[epico]

Thanks for the patch!