Revert "Fixing Facts pson methods more resilient"

This reverts commit 07a7a68a25eb9b21189751c27f90f972224ea533.
The JSON patch series has caused problems with the inventory service,
and further discussion is needed to decide how to serialize objects to
PSON with regards to future compatibility.

Conflicts:

spec/unit/node/facts_spec.rb

Paired-with:Matt Robinson <matt@puppetlabs.com>