vote on TS-1368,TS-1433,TS-1609
promote/clone jiras
step one: Remove ifdefs, fail. Step two: ???. Step three: RAW Disk Support on FreeBSD
remove old, obsolete ways of retrieving disk-size information

on FreeBSD there used to be very arcane handling of disk related
information. Starting 5.1 this was all obsoleted, our code however,
having been stashed, was not updated.
This commit simplified the retrieval of the size information,
using phk's ~src/usr.sbin/diskinfo code as example.
get and use hw_sector_size, set disk_id

get hw_sector_size from ioctl
use it in the calculation, rather than the #define

We also forgot to set the disk_id
TS-1655  RAW disk support for FreeBSD

backport of: 1b9fa981cde26ae475ab300015863813ded31a9d
	 26849e983a1d59918a9260f59b3f896b0f550d0c
	 690ccc26082c75a93053bb7643c848b34cfca100
test/review: igalic, jpeach, oschaaf
backport: igalic