There's some leftover cruft at the tail end of the halt script:
if [ -f /poweroff -o ! -f /halt ]; then
The halt command does not have the -p option. This is superceeded by the
Additionally, there's nothing that creates /poweroff. This should be an
option to shutdown.
The halt command certainly claims to have a -p option.
As for something that creates /poweroff, look at
the SysVinit source. :)