"Ready to reboot" message should be changed.

[suikan4github]

In the post_install() function, it displays "Ready to reboot" message.

Actually, after this message, we show several messages from Kaiten-yaki.

These messages should be corrected.

1. "Ready to reboot" should be changed to "Post-install process is complete"
2. In the main() function, display "Read to reboot".

[suikan4github]

Merged to develop. Ready to release.