Bug#182839: kbd-chooser: Segfault when running with DEBCONF_PRIORITY=high

[Petter Reinholdtsen <pere@hungry.com>]

Package: kbd-chooser
Version: 0.009
Severity: serious

When installing d-i using DEBCONF_PRIORITY=high, the kdb-chooser
package segfaults.  This is the messages when using the text frontend:

  mount: Mounting usbdevfs on /proc/bus/usb failed: No such file or directory
  installer[2302]: Failed to mount USB filesystem
  installer[2302]: Setting no keybd case
  Select a Keyboard Layout

  Choose the type of keyboard to configure
    1. [ps2] PC Style (PS2/connector) (default)
    2. [usb] USB
    3. [none] No keyboard to configure
  Prompt: 1 - 3> Segmentation fault

When I press enter to continue, the installer continues with the next
package.  The error situation was not passed on to main-menu.

I believe the priority of the displayed question is to high.  It
should be priority medium, as the default shoul be OK in most cases.