install/47684: sysinst once again prints "(null)"

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

>Number:         47684
>Category:       install
>Synopsis:       sysinst once again prints "(null)"
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    install-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Mar 22 14:30:00 +0000 2013
>Originator:     Andreas Gustafsson
>Release:        NetBSD-current >= 2013.03.19.22.16.55
>Organization:
>Environment:
System: NetBSD
Architecture: i386
Machine: i386
>Description:

Since the commits of 2013-03-19 22:16:53 through 22:16:55 by garbled,
the output from sysinst contains the string "(null)".  It occurs after
the "Add a user" menu item, as in the following example output
(non-printable terminal control characters have been replaced by
printable representations):

   k: Add a user^[[15;56H(null)^M^M

Since the typical cause for (null) occurring in program output
is the illegal passing of a null pointer to a printf %s format,
I'm assuming this is a bug.

The reason the PR synopsis says "once again" is to distinguish 
it from the long since fixed PR 6432.

>How-To-Repeat:

Do an "anita install" of a -current i386 build, redirecting output to a
log file, and run fgrep -c '(null)' on the log file.  Presumably doing
a manual install will also work.

>Fix: