Remove has_rdoc entry from the gemspec

Author: seejohnrun

ice_cube.gemspec

@@ -17,7 +17,6 @@ Gem::Specification.new do |s|
   s.files         = Dir['lib/**/*.rb', 'config/**/*.yml']
   s.test_files    = Dir.glob('spec/*.rb')
   s.require_paths = ['lib']
-  s.has_rdoc      = true
 
   s.add_development_dependency('rake')
   s.add_development_dependency('rspec', '> 3')