OpenSSL::PKey::DH.new(2048) takes forever, and we pre-generate
test keys for other SSL-using tests anyways.
* test/rubygems/test_gem_remote_fetcher.rb: pre-generate test key
[ruby-core:70151] [Bug #11397]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51414 b2dd03c8-39d4-4d8f-98ff-823fe69b080e