(CFACT-102) Remove partitions from the solaris facts

Previously, the disks section of facts listed the available partitions, as
obtained from kstat. However further investigation revealed that the partitions
reported by kstat did not give a true picture of disk partitions. Further, the
partitions given by kstat included both slices and partitions. Further there is
an ambiguity regarding the terminology, and there are different kinds of slices
and partitions too. Hence, the partition section of disks should not be exposed
at this time (pending further investigation).

This patch removes the partitions listed in disks section.
(maint) Remove header guards in favor of #pragma once.

Removing header guards in favor of #pragma once, which is supported by
every compiler we use.
Merge pull request #138 from vrthra/fix/cfact-102/solaris-remove-partition

(CFACT-102) Remove partitions from the solaris facts
Merge pull request #139 from peterhuene/pragma/once

(maint) Remove header guards in favor of #pragma once.
(CFACT 119) Add zone facts for solaris

This patch adds zone facts for solaris. Since zones do not provide a C API, we
use zone commands to fetch this information.