these versions of nokogiri don't build on travis

Author: JonRowe

Gemfile

@@ -32,7 +32,7 @@ if RUBY_VERSION < '1.9.2'
 elsif RUBY_VERSION < '1.9.3'
   gem 'nokogiri', '1.5.2'
 else
-  gem 'nokogiri', ['~> 1.5', '< 1.6.6.3', '> 1.6.6.4']
+  gem 'nokogiri', ['~> 1.5', '!= 1.6.6.3', '!= 1.6.6.4']
 end
 
 if RUBY_VERSION <= '1.8.7'