no /netbsd on amd64 boot ISO

["Jeremy C. Reed" <reed%reedmedia.net@localhost>]

The last two ISO images I made have no /netbsd. The primary bootstrap 
loads but doesn't find any kernel. That is NetBSD-6.99.6-amd64.iso and 
NetBSD-6.99.7-amd64.iso.

> ls
2 . (DIR)
2: .. (DIR)
3: boot (REG)
193536: cdrom (DIR)
86016: dev (DIR)
21504: etc (DIR)
43008: kern (DIR)
64512: proc (DIR)
> ls cdrom
193536: . (DIR)
2: .. (DIR)


Well I just downloaded NetBSD-6.0_BETA-amd64.iso from today's releng 
build. Same problem.  (What can we do automate tests of these 
releng ISOs?)