* lib/net/smtp.rb (tlsconnect): support timeout for TLS handshake.
[ruby-core:76893] [Bug #12678]
* lib/net/protocol.rb (ssl_socket_connect): new method to implement
timeout for TLS handshake.
* lib/net/http.rb (connect): use Net::Protocol#ssl_socket_connect.
* test/net/smtp/test_smtp.rb (test_tls_connect, test_tls_connect):
use Socket.tcp_server_sockets in case localhost is resolved to ::1.
merge revision(s) 56576,56623: [Backport #12678] [Backport #13429]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_3@59533 b2dd03c8-39d4-4d8f-98ff-823fe69b080e