Remove RUBY_VERSION check for ruby 1.8
Remove RUBY_VERSION check for ruby 1.8

Currently we do not support ruby 1.8 and do not
run tests against ruby 1.8.
So we do not need to check RUBY_VERSION for ruby 1.8.

Shopify/oj,enebo/oj,Shopify/oj,ohler55/oj,Shopify/oj,enebo/oj,enebo/oj,enebo/oj,ohler55/oj,ohler55/oj