Metadata typo

Fixes logstash-plugins#94

Author: nfsec

spec/inputs/tcp_spec.rb

@@ -76,7 +76,7 @@ def get_port
       event = events[i]
       insist { event.get("message") } == "#{i} ☹"
       insist { event.get("host") } == host
-      insist { event.get("[@metdata][ip_address]") } == '127.0.0.1'
+      insist { event.get("[@metadata][ip_address]") } == '127.0.0.1'
     end
   end