ca option and reporting errors no ECONNREFUSED

I added the ```ca``` options to provide an array with the CAs that
winston-logstash secure socket accept, so it is provided to node client
secure socket connection.

I also added a checking in socket ```error``` listener to report to
transport eventEmitter when socket received an error different from
ECONNREFUSED

lib/winston-logstash.js

@@ -13,6 +13,8 @@ var net = require('net'),
     winston = require('winston'),
     common = require('winston/lib/winston/common');
 
+var ECONNREFUSED_REGEXP = /ECONNREFUSED/;
+
 var Logstash = exports.Logstash = function (options) {
   winston.Transport.call(this, options);
   options = options || {};
@@ -27,6 +29,7 @@ var Logstash = exports.Logstash = function (options) {
   this.ssl_enable          = options.ssl_enable || false;
   this.ssl_key             = options.ssl_key || '';
   this.ssl_cert            = options.ssl_cert || '';
+  this.ca                  = options.ca || '';
   this.ssl_passphrase      = options.ssl_passphrase || '';
 
   // Connection state
@@ -84,6 +87,7 @@ Logstash.prototype.log = function (level, msg, meta, callback) {
 };
 
 Logstash.prototype.connect = function () {
+  var tryReconnect = true;
   var options = {};
   var self = this;
   this.retries++;
@@ -92,7 +96,16 @@ Logstash.prototype.connect = function () {
     options = {
       key: this.ssl_key ? fs.readFileSync(this.ssl_key) : null,
       cert: this.ssl_cert ? fs.readFileSync(this.ssl_cert) : null,
-      passphrase: this.ssl_passphrase ? this.ssl_passphrase : null
+      passphrase: this.ssl_passphrase ? this.ssl_passphrase : null,
+      ca: this.ca ? (function (caList) {
+        var caFilesList = [];
+
+        caList.forEach(function (filePath) {
+          caFilesList.push(fs.readFileSync(filePath));
+        });
+
+        return caFilesList;
+      }(this.ca)) : null
     }
     this.socket = new tls.connect(this.port, this.host, options, function() {
       self.socket.setEncoding('UTF-8');
@@ -108,6 +121,11 @@ Logstash.prototype.connect = function () {
     self.connected = false;
     self.socket.destroy();
     self.socket = null;
+
+    if (!ECONNREFUSED_REGEXP.test(err.message)) {
+      tryReconnect = false;
+      self.emit('error', err);
+    } 
   });
 
   this.socket.on('timeout', function() {
@@ -119,7 +137,7 @@ Logstash.prototype.connect = function () {
   this.socket.on('close', function (had_error) {
     self.connected = false;
 
-    if (self.max_connect_retries === -1 || self.retries < self.max_connect_retries) {
+    if ((tryReconnect) && (self.max_connect_retries === -1 || self.retries < self.max_connect_retries)) {
       if (!self.connecting) {
         setTimeout(function () {
           self.connect();