Cannot bind SSL port due to missing verify_mode option

[frankwong15]

Related to #832

Reproduced in frankwong15/rails-puma

frank@frank-nb:~/projects/rails-puma$ puma -C config/puma.rb 
Puma starting in single mode...
* Version 3.4.0 (jruby 1.9.3), codename: Owl Bowl Brawl
* Min threads: 0, max threads: 16
* Environment: development
DEPRECATION WARNING:
Sass 3.5 will no longer support Ruby 1.9.3.
Please upgrade to Ruby 2.0.0 or greater as soon as possible.

* Listening on tcp://0.0.0.0:8080
* Listening on ssl://0.0.0.0:8443?keystore=keystore.jks&keystore-pass=password
Use Ctrl-C to stop
2016-04-23 15:23:43 +0800: Listen loop error: #<TypeError: can't convert nil into Integer>
org/jruby/puma/MiniSSL.java:162:in `initialize'
org/jruby/puma/MiniSSL.java:131:in `server'
/home/frank/.rvm/gems/jruby-1.7.19/gems/puma-3.4.0-java/lib/puma/minissl.rb:167:in `accept_nonblock'
/home/frank/.rvm/gems/jruby-1.7.19/gems/puma-3.4.0-java/lib/puma/server.rb:329:in `handle_servers'
org/jruby/RubyArray.java:1613:in `each'
/home/frank/.rvm/gems/jruby-1.7.19/gems/puma-3.4.0-java/lib/puma/server.rb:324:in `handle_servers'
/home/frank/.rvm/gems/jruby-1.7.19/gems/puma-3.4.0-java/lib/puma/server.rb:297:in `run'