Bug#281538: languagechooser: [s390] Invalid setup of localization

[Frans Pop <aragorn@tiscali.nl>]

Package: languagechooser
Version: 1.42

During an s390 installation (see #281530), languagechooser and 
countrychooser are not run as they are not on the initrd.
However, they are loaded later in the process and languagechooser's 
prebaseconfig _is_ run at the end of 1st stage installation.

This probably means that some debconf values and environment variables 
which languagechooser expects to be set, are not set.
The prebaseconfig does not handle this situation correctly.

The syslog for the install showed:
info: Running /usr/lib/prebaseconfig.d/05languagechooser
warning: /usr/lib/prebaseconfig.d/05languagechooser returned error code 1

First problem
=============
/etc/environment is set up with LANG="" and LANGUAGE=""

IMHO it would be better if LANG was set to "C" and LANGUAGE maybe not set 
at all.

Second problem
==============
/etc/localegen is set up with 'Usage: /usr/sbin/validlocale <locale>'

During package installation in tasksel, locales was installed.
During the preconfig of locales, the top of the list of locales to choose 
from showed: [*] Usage: /usr/sbin/validlocale <locale>

It appears this line was added to /etc/localegen during prebaseconfig, by 
calling 'validlocale $LANG' instead of 'validlocale "$LANG"' (and by not 
checking the return code of validlocale).

Note that this problem would disappear if LANG were set to C.
However, a check for the return code should be added anyway.