[OE-core] Busybox mdev INITSCRIPT_PARAMS gets lost

[Mike Looijmans]

In busybox.inc, the recipe says:

INITSCRIPT_PARAMS_${PN}-mdev = "start 06 S ."

Actually "06" is alreay wrong, it should be "03" just like udev uses. 
The modules load at runlevel 04, so they'll fail to load correctly if 
they require firmware, soI amended this in a .bbappend to read

INITSCRIPT_PARAMS_${PN}-mdev = "start 03 S ."


But what ends up in the postinstall script is this (and that breaks the 
system):

update-rc.d $OPT mdev defaults

This used to work just fine about a month ago, but it's suddenly broken. 
Has something changed in update-rc handling?

Mike.