Remove deprecated has_rdoc.

Author: ioquatix

rubydns.gemspec

@@ -17,7 +17,6 @@ Gem::Specification.new do |spec|
 	spec.executables   = spec.files.grep(%r{^bin/}).map{ |f| File.basename(f) }
 	spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
 	spec.require_paths = ["lib"]
-	spec.has_rdoc = "yard"
 
 	spec.add_dependency("async-dns", "~> 1.0")
 	spec.add_development_dependency("async-rspec", "~> 1.0")