Currently, the fips_resolver on facter-ng raises with ENOENT if File.read cannot find /proc/sys/crypto/fips_enabled, and the Facter run ends. If we can't find that file, we should assume that fips_enabled is false.
Relevant code bit: https://github.com/puppetlabs/facter-ng/blob/master/lib/resolvers/fips_enabled_resolver.rb#L21