fixed key shortcut to start/end game (broken by regression)

This change fixes a regression of commit 888ee049 (and 35da46e4) that
causes problems when handling text input in situations unrelated to
the Android screen keyboard, like entering key shortcuts to start and
end a game on non-Android platforms.

This commit fixes a bug that results in restarting the game when the
player has died and the "space" key (or other configured key) was used
to return to the main menu (or level editor).