Rename k5-queue.h macros

Rename k5-queue.h macros

Some BSD-derived systems (e.g., FreeBSD and Mac OS X) inappropriately
include sys/queue.h from some non-kernel network-related headers that
we include (net/if.h is one example).  Because our k5-queue.h is a
copy from a BSD sys/queue.h, many compilers will warn about macro
redefinitions on those systems.  Rename the queue macros to have a K5_
prefix.

Also delete the QUEUEDEBUG macros because they are only useful for
kernel use on the BSD systems where this header originated.

ticket: 8466 (new)