A recent version of the oldnfs NFS client in head/current
will crash when doing a large write, since m_get2() would
return NULL. This patch fixes the problem, since nfsm_uiotombuf()
will allocate additional mbufs, as required.

Reported by:	sbruno
Tested by:	sbruno
Discussed with:	glebius
Correct a typo in comment.
Add syslog(3) support to devd(8).

sbin/devd/devd.cc
        All output will now go to syslog(3) if devd is daemonized, or stderr
        if it's running in the foreground.

sbin/devd/devd.8
        Remove the "-D" flag.  Filtering messages by priority now
	happens in the usual syslog way.  For performance reasons, a few
	extra-verbose debugging statements are now conditional on the "-d" (do
	not daemonize) flag.

etc/syslog.conf
etc/newsyslog.conf
        Direct messages from devd(8) to /var/log/devd.log, but leave it
        disabled by default

Reviewed by:	eadler
Approved by:	gibbs (co-mentor)
MFC after:	never (removed a command-line option from devd)