delete 2 macros from queue.h

[Stepan A. Baranov]

Hello,

I made the Russian translation of queue(3) and found out that in
sys/sys/queue.h there are macros SLIST_FOREACH_PREVPTR and
STAILQ_REMOVE_HEAD_UNTIL which are not described in queue(3). The
macros SLIST_FOREACH_PREVPTR is used only in sys/kern/sysv_sem.c and
the macros STAILQ_REMOVE_HEAD_UNTIL is used only in
sys/dev/ubsec/ubsec.c . Thus, I think that these macros must be
described in queue(3) or be deleted.
I made the patch for removing such macros from sys/sys/queue.h . The
patch can be fetched from
http://www.rosmir.org/freebsd/patches/patch-queue . Please, test it
and fix it.

Stepan Baranov.