Issues with ssl_certificate_validation in logstash output elasticsearch plugin

@magnusbaeck @andrewvc - Please suggest

Logstash Version : 2.3.2

Using below configuration in logstash conf file :
elasticsearch {
hosts => ["https://es-XXXXX:443"]
ssl_certificate_verification => false
index => "XXXX"
user => "user"
password => "password"
}

https://es-XXXXX:443 is a vip pointing to elastic data nodes x.x.x.x:9200
ssl_certificate_verification setting is not working and below error

{:timestamp=>"2016-05-20T17:03:07.973000+0000", :message=>"PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target", :class=>"Manticore::ClientProtocolException", :backtrace=>["/u01/logstash-2.3.2/vendor/bundle/jruby/1.9/gems/manticore-0.5.5-java/lib/manticore/response.rb:37:in `initialize'", "org/jruby/RubyProc.java:281:i

Also , am able to curl vip ip successfully:

curl -u user:password--insecure https://es-XXXXX:443
{
"name" : "",
"cluster_name" : "",
"version" : {
"number" : "2.3.2",
"build_hash" : "xx",
"build_timestamp" : "",
"build_snapshot" : false,
"lucene_version" : "5.5.0"
},
"tagline" : "You Know, for Search"
}

Similar Issue - https://github.com/logstash-plugins/logstash-output-http/issues/21