Allow unused space in a partition to equal its size

Newly created LVM2 PVs, before being added to a Volume Group, report
free space equal to the partition size.  Allow free space to equal
partition size.

    # parted /dev/sda10 unit B print
    Error: /dev/sda10: unrecognised disk label
    Model: Unknown (unknown)
    Disk /dev/sda10: 2147483648B
    Sector size (logical/physical): 512B/512B
    Partition Table: unknown
    # lvm pvcreate /dev/sda10
      Writing physical volume data to disk "/dev/sda10"
      Physical volume "/dev/sda10" successfully created
    # lvm pvs --units b -o pv_free /dev/sda10
      PFree
      2147483648B