Start ES embedded server before creating a client.

This resolves a startup-delay problem where Node/Transport protocols
would attempt to find a master before continuing, having no master,
After this patch:
waits for a timeout.

Manual test:
    % time bin/logstash -e 'input { generator {  count => 1 } } output { elasticsearch { embedded => true } }'

Before this patch:
    WARN: org.elasticsearch.discovery: [logstash-ds4172-27071-2010]
    waited for 30s and no initial state was set by the discovery

    bin/logstash -e   20.50s user 0.70s system 45% cpu 46.793 total

After this patch:
    bin/logstash -e   21.53s user 0.52s system 115% cpu 19.070 total

lib/logstash/outputs/elasticsearch.rb

@@ -234,12 +234,6 @@ class LogStash::Outputs::ElasticSearch < LogStash::Outputs::Base
         LogStash::Outputs::Elasticsearch::Protocols::HTTPClient
     end
 
-    @client = client_class.new(options)
-
-    @logger.info("New Elasticsearch output", :cluster => @cluster,
-                 :host => @host, :port => @port, :embedded => @embedded,
-                 :protocol => @protocol)
-
     if @embedded
       raise(LogStash::ConfigurationError, "The 'embedded => true' setting is only valid for the elasticsearch output under JRuby. You are running #{RUBY_DESCRIPTION}") unless LogStash::Environment.jruby?
       LogStash::Environment.load_elasticsearch_jars!
@@ -253,6 +247,12 @@ class LogStash::Outputs::ElasticSearch < LogStash::Outputs::Base
       start_local_elasticsearch
     end
 
+    @client = client_class.new(options)
+
+    @logger.info("New Elasticsearch output", :cluster => @cluster,
+                 :host => @host, :port => @port, :embedded => @embedded,
+                 :protocol => @protocol)
+
 
     if @manage_template
       @logger.info("Automatic template management enabled", :manage_template => @manage_template.to_s)