(#16809) Refactor crontab provider with block_eval

Ruby 1.9 was failing to parse the previous implementation of the custom
crontab record_line provider methods. This commit uses the FileParsing
block_eval syntax to attach methods to the record_line object instead of
using anonymous procs.
(#16809) Remove refs to freebsd_special cron type

The legacy test::unit crontab tests contained checks for the
freebsd_special record line. Since those were not getting run by the
normal rspec coverage it got missed when the freebsd_special line type
was removed. This commit removes the outdated references.