install/45816: Screen corruption in German sysinst install

[gson%gson.org@localhost (Andreas Gustafsson)]

>Number:         45816
>Category:       install
>Synopsis:       Screen corruption in German sysinst install
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    install-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Jan 11 15:50:00 +0000 2012
>Originator:     Andreas Gustafsson
>Release:        NetBSD-current, source date 2012.01.09.11.52.43
>Organization:
>Environment:
Architecture: i386
Machine: i386
>Description:

See the "How-To-Repeat" section below.  I noticed this behavior while
testing my recent sysinst changes adding support for installing the
source sets, but testing a version without my changes gave the same
result.  "It was like this when I got here, I swear!"

>How-To-Repeat:

Start installing -current/i386 on a PC using sysinst from
the PC console (not a serial console).

Select German as the installation language.

Proceed with the installation to the point where you select the
location of the install sets ("Medium auswahlen").  Select
"a: CD-ROM / DVD".

You will now see a screen where you can select the CD drive and
path(s).  The cursor is positioned on the menu item for selecting the
drive: "Gerat cd0a" (with umlaut where appropriate).

Press enter to change the drive.  You will see a pop-up window
saying "Laufwerk [cd0a]:".

Press enter again to accept the default.

Note how there is now a stray close parenthesis in the rightmost
column of the screen.

Press enter two more times.

Note how a second copy of the text from the top of the screen ("Geben
Sie das CD-Laufwerk...") has now appeared below the menu.

Press enter a few more times and see how yet more copies of the text
keep appearing on the screen.

>Fix: