(PUP-11620) Avoid sending malformed PuppetDB reports with Oj

This disables the conversion of floats to BigDecimal when the Oj
MultiJson adapter is being used, as is done currently with JrJackson.

The original bug report is at the following URL:
https://bugs.debian.org/923976

This patch has been carried for some time in the Debian Puppet package,
without issue.

Author: apoikos

lib/puppet/util/json.rb

@@ -49,13 +49,16 @@ def self.load_file(filename, options = {})
     def self.load(string, options = {})
       if defined? MultiJson
         begin
-          # This ensures that JrJackson will parse very large or very small
+          # This ensures that JrJackson and Oj will parse very large or very small
           # numbers as floats rather than BigDecimals, which are serialized as
           # strings by the built-in JSON gem and therefore can cause schema errors,
           # for example, when we are rendering reports to JSON using `to_pson` in
           # PuppetDB.
-          if MultiJson.adapter.name == "MultiJson::Adapters::JrJackson"
+          case MultiJson.adapter.name
+          when "MultiJson::Adapters::JrJackson"
             options[:use_bigdecimal] = false
+          when "MultiJson::Adapters::Oj"
+            options[:bigdecimal_load] = :float
           end
 
           MultiJson.load(string, options)