Avoid loop between pool.destroy and client.end

lib/pool.js

@@ -35,13 +35,18 @@ var pools = {
 
           // Remove connection from pool on disconnect
           client.on('end', function(e) {
-            pool.destroy(client);
+            // Do not enter infinite loop between pool.destroy
+            // and client 'end' event...
+            if ( ! client._destroying ) {
+              pool.destroy(client);
+            }
           });
 
           return cb(null, client);
         });
       },
       destroy: function(client) {
+        client._destroying = true;
         client.end();
       }
     });