Fixes #1

Had got things stuck in a loop whereby on connection close I tried
to lookup the peer address for the log message; this in turn raised
a new connection close. Now I'm caching the peer address from when
the connection was first established.

Author: MikeWorth

lib/logstash/util/relp.rb

@@ -95,11 +95,10 @@ def server?
 class RelpServer < Relp
 
   def peer
-    begin
-      @socket.peeraddr[3]#TODO: is this the best thing to report? I don't think so...
-    rescue IOError
-      raise ConnectionClosed
+    if @peer.nil?
+      @peer = @socket.peeraddr[3]#TODO: is this the best thing to report? I don't think so...
     end
+    @peer
   end
 
   def initialize(host,port,required_commands=[])