resolv.rb: dots differences

* lib/resolv.rb (Resolv::DNS::Name): names with different dots
  should be different.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49071 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
test_dns.rb: test name

* test/resolv/test_dns.rb (TestResolvDNS#test_dots_diffences): fix
  test name.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49072 b2dd03c8-39d4-4d8f-98ff-823fe69b080e