different things from this commit:
+ More devices. Devices that were previously ignored are now present.
+ Faster device scanning. "There is no try, only Do" -- f_device_try()
is no longer the basis of device scanning as GEOM provides [nearly]
all devices (doesn't provide network devices).
+ More information available as non-root. Usually you have to be root
to do things like taste filesystems, and that limits the amount of
information available to non-root users; with GEOM, we see all even
running unprivileged as the brunt of information (except for so-
called ``dangerously dedicated'' file systems) is represented by the
`kern.geom.confxml' sysctl(8) MIB.
NB: Only really useful for external scripts that use the API and run as
non-root; where this code is used in bsdconfig(8) and bsdinstall(8)
you are running as root so can detect even ``dangerously dedicated''
file systems that are not present in GEOM; e.g., no PART class for
a DOS filesystem written directly to disk without partition table).
+ No more use of legacy tools such as diskinfo(8) to get disk capacity
or fdisk(8) to see partitions.
MFC after: 1 week
9ecd54f24f