rogue[345]: fix backspace key in prompts. md_readchar() mapped KEY_BACKSPACE to CTRL-H, but get_str(), which handles prompts for strings, only backs up when it receives the erase character. The key should be mapped to md_erasechar(). This fixes Red Hat Bugzilla #847852.

[Desktop Entry]
Encoding=UTF-8
Name=Rogue
GenericName=Rogue
Comment=The original curses-based adventure game
Exec=rogue
Icon=rogue.png
Terminal=true
Type=Application
Categories=Game;RolePlaying;
Version=1.0