Fix for AIX machines with IPv6 disabled.

This attempts to handle the fact that NTP seems to explode if IPv6
is disabled on AIX, ntp becomes unable to parse the -6 lines that
we rely on in $restrict.  It also apparently predates the KoD filtering
capabilities.  As this stands for 'Kiss of Death' we certainly want to
retain this filtering capability for other distributions and operating
systems.
Fix this to use the puppetpath correctly.
Merge pull request #142 from apenney/aix-ipv6-fixes

Fix for AIX machines with IPv6 disabled.