Default to TLS 1.2 which is now the default in Java 8

[suyograo]

Today LS defaults to TLS 1.1 for securing communication over http. We should default to TLS 1.2. Java 8 will already default to it: https://blogs.oracle.com/java-platform-group/entry/java_8_will_use_tls

@jordansissel had previously mentioned there were some issues in JRuby for supporting TLS 1.2, but we they may have been resolved now. See jruby/jruby#1737

[suyograo]

suyog@machine:~$ irb
jruby-1.7.22 :001 > require "openssl"
 => true
jruby-1.7.22 :002 > OpenSSL::SSL::SSLContext.new.ssl_version=:"TLSv1_2"
 => :TLSv1_2