* lib/net/http/exceptions.rb: revert a part of r63590. to deprecate Net::ProtoServerError seems to be wrong. see [ruby-core:87488] [Feature#14688] git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63661 b2dd03c8-39d4-4d8f-98ff-823fe69b080e