sysv_{ipc|shm}: update the NetBSD VCS tags to match nearer our files.

Both files originated in NetBSD:

sysv_ipc.c CVS 1.9:
Most of their changes don't apply to us as we already have similar
changes. This is a better reference for future merges.

sysv_shm.c CVS 1.39:
Most of their changes don't apply to our code but interestingly this
revision merged our changes and is a better point for reference.

Move the VCS tags to the position recommended in our committers guide
(section 8),

No functional change.