Fix ternary operator

Fixes #457

Author: untergeek

lib/logstash/outputs/elasticsearch/template_manager.rb

@@ -30,7 +30,7 @@ def self.install(client, template_name, template, template_overwrite)
     end
 
     def self.default_template_path(es_major_version)
-      es_major_version == "1" ? template_version = "2" : template_version = es_major_version
+      template_version = es_major_version == "1" ? "2" : es_major_version
       default_template_name = "elasticsearch-template-es#{template_version}x.json"
       ::File.expand_path(default_template_name, ::File.dirname(__FILE__))
     end