drop support for Ruby 2.2.2

- Removed Ruby 2.2.2 from Gemfile

Author: martencassel

Gemfile

@@ -2,11 +2,6 @@ source 'https://rubygems.org'
 gemspec
 
 group :development do
-  if RUBY_VERSION < '2.2.2'
-    gem 'rack-test', '~> 0.7.0'
-  else
-    gem 'rack-test'
-  end
-
+  gem 'rack-test'
   gem 'smart_proxy', :git => 'https://github.com/theforeman/smart-proxy.git', :branch => 'develop'
 end