Make zpool list -vp print individual vdev sizes parsable.

Add argument format to print_one_column(), and use it to call
zfs_nicenum_format with, instead of just zfs_nicenum. Don't print "%"
for fragmentation or capacity percent values.

The calls to print_one_colum is made with ZFS_NICENUM_RAW if
cb->cb_literal (zpool list called with -p), and ZFS_NICENUM_1024 if not.

Also zpool_get_prop is modified to don't add "%" or "x" if literal.

Signed-off-by: Christer Ekholm <che@chrekh.se>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov
Closes #4657