Log Message:
Fix the mk/pkginstall variables used in net/nagios-base.

* Ensure that ${PKG_SYSCONFDIR}/objects is created at package
  installation time by adding it to OWN_DIRS.

* Don't explicitly add ${DESTDIR} to files listed in SPECIAL_PERMS
  since it is automatically added by the pkgsrc infrastructure if
  needed.

* It's "${DESTDIR}${PREFIX}", not "${DESTDIR}/${PREFIX}" -- avoid
  having double slashes in pathnames for correctness.

Bump the PKGREVISION due to fixes in the package install scripts.
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