Merge pull request #358 from vincentwoo/patch-1

Check jruby a different way

Author: nahi

lib/httpclient/session.rb

@@ -21,7 +21,7 @@
 require 'httpclient/timeout' # TODO: remove this once we drop 1.8 support
 require 'httpclient/ssl_config'
 require 'httpclient/http'
-if RUBY_ENGINE == 'jruby'
+if defined? JRUBY_VERSION
   require 'httpclient/jruby_ssl_socket'
 else
   require 'httpclient/ssl_socket'