Revert "Fix for https://github.com/example42/puppet-ntp/issues/12"

This reverts commit 22762a5724a30b8e0e5320d0b676d76ee37ebafb.
Fix for https://github.com/example42/puppet-ntp/issues/12

... without unnecessary installing ntpdate on Debian
Merge pull request #13 from sathieu/for_upstream

ntpdate