libparted: gpt: rewrite even a 9-partition-entry table properly

libparted: gpt: rewrite even a 9-partition-entry table properly

The vast majority of GPT partition tables have 128 PTEs (partition
table entries.  However, zfs-related ones have only 9, and when
rewriting one (which can happen only in interactive mode), parted
would fail to write the full PTE array whenever the PTE array size
was not a multiple of the sector size.  This fixes the same type
of bug as v3.0-45-gce85c51.
* libparted/labels/gpt.c (gpt_write): When computing how many sectors
to write for the PTE array, round up rather than truncating.  This
matters only when n_PTEs * 128 is not a multiple of the sector size.
For details on how to reproduce see the test or
http://thread.gmane.org/gmane.comp.gnu.parted.bugs/10691/focus=10695
* NEWS (Bug fixes): Mention it.