Description of problem:
Custome Boolean Puppet facts with value False are not on the WebUI, Hammer output or with REST API. Only facts with value True are shown/stored.

Version-Release number of selected component (if applicable):
Satellite 6.4
Puppet 5

How reproducible:
Always

Steps to Reproduce:
In /opt/puppetlabs/puppet/cache/lib/facter 

# cat temp.rb
require 'facter'

Facter.add("always_true") do
  confine :kernel => "Linux"
  setcode do
    true
  end
end

Facter.add("always_false") do
  confine :kernel => "Linux"
  setcode do
    false
  end
end

Actual results:
- False value is not displayed
# hammer fact list --search "name=always_true"
----------------------|-------------|------
HOST                  | FACT        | VALUE
----------------------|-------------|------
lvmpig03 | always_true | true
----------------------|-------------|------

Expected results:
- False value should be displayed
# hammer fact list --search "name=always_false"
----------------------|-------------|------
HOST                  | FACT        | VALUE
----------------------|-------------|------
lvmpig03 | always_false | false
lvmpig03 | always_true | true
----------------------|-------------|------