Update kerberos/ssh/pam issue: this is errata for 5.0 because of the
risk of moving to a threaded sshd close to the release date. Add
mention of a potential new problem raised on freebsd-current
regarding ssh authentication sometimes failing with an ssh socket
write error.

Remove 5.0 documentation task: most of what's left is covered by
other task items, and we've hit a number of the big name issues
(devfs, mdmfs, etc).

Change the status of the truss item: there are potential fixes, but
they were deemed too risky this close to the release because they
changed parts of the fork and exec code paths.

Add a comment to the iir entry appealing for hardware for developers.

Remove the RC1 perl package issue: that's now resolved.