lib/52401: Booting install media fails with "init died"

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

>Number:         52401
>Category:       lib
>Synopsis:       Booting install media fails with "init died"
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    lib-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Jul 14 08:15:00 +0000 2017
>Originator:     Andreas Gustafsson
>Release:        NetBSD-current, source date >= 2017.07.11.15.21.36
>Organization:

>Environment:
System: NetBSD
Architecture: sparc
Machine: sparc
>Description:

Since joerg's commit of 2017.07.11.15.21.36, the sparc tests on
babylon5.netbsd.org are failing with "init died" at the install stage:

  http://releng.netbsd.org/b5reports/sparc/build/2017.07.11.15.21.36/install.log

I am also seeing a similar issue with hpcmips (on qemu), which leads
me to believe the issue is not specific to sparc.  The PR category
"lib" is my best guess based on the files changed by the commit.

>How-To-Repeat:

Attempt to install NetBSD-current/sparc.

>Fix: