(CFACT 70) Add the kstat kernel information library to solaris linking

KStat provides information that is useful for resolving several
facts about the solaris kernel. This patch links the kstat library to cfacter
(CFACT 70) publish uptime fact for solaris

Before this patch, solaris10 did not report uptime. This patch adds the support
of uptime fact to solaris. It does this by relying on kstat library, which is
used to lookup kernel information. If the library call fails, it relies on
/bin/uptime for the uptime fact.
Merge pull request #110 from vrthra/fix/cfact-70/add-uptime-fact

(CFACT-70) add uptime fact for solaris