fixup! Guard rack with < 2 for Ruby < 2.2.2

Author: knu

omniauth-oauth2.gemspec

@@ -5,7 +5,7 @@ require "omniauth-oauth2/version"
 Gem::Specification.new do |gem|
   gem.add_dependency "oauth2",     "~> 1.0"
   gem.add_dependency "omniauth",   "~> 1.2"
-  gem.add_dependency "rack",       "< 2" if RUBY_VERSION < '2.2.2'
+  gem.add_dependency "rack",       "< 2" if RUBY_VERSION < "2.2.2"
 
   gem.add_development_dependency "bundler", "~> 1.0"