Reset retries connect and emit error when silent mode

I added the 'connect' event listener to socket to reset the connection
retries counter and 'error' emit to the transport when the maximum
connect retries is reached and the transport is 'silent' mode

lib/winston-logstash.js

@@ -116,6 +116,10 @@ Logstash.prototype.connect = function () {
     }
   });
 
+  this.socket.on('connect', function () {
+    self.retries = 0;
+  });
+
   this.socket.on('close', function (had_error) {
     self.connected = false;
 
@@ -128,6 +132,7 @@ Logstash.prototype.connect = function () {
     } else {
       self.log_queue = [];
       self.silent = true;
+      self.emit('error', new Error('Max retries reached, transport in silent mode, OFFLINE'));
     }
   });