Rakefile in ably-0.8.4 vs Rakefile in ably-0.8.5

@@ -14,10 +14,10 @@
   task :default => :spec
 
   namespace :doc do
     desc 'Generate Markdown Specification from the RSpec public API tests'
     task :spec do
-      ENV['TEST_LIMIT_PROTOCOLS'] = JSON.dump({ msgpack: 'JSON and MsgPack' })
+      ENV['PROTOCOL'] = 'json'
 
       rspec_task.rspec_opts = %w(
         --require ./spec/support/markdown_spec_formatter
         --order defined
         --tag ~api_private