Stop retry timer with operation.stop() (#69)

Fix tim-kos/node-retry/#64

Author: danielfdsilva

lib/retry_operation.js

@@ -15,6 +15,7 @@ function RetryOperation(timeouts, options) {
   this._operationTimeoutCb = null;
   this._timeout = null;
   this._operationStart = null;
+  this._timer = null;
 
   if (this._options.forever) {
     this._cachedTimeouts = this._timeouts.slice(0);
@@ -31,6 +32,9 @@ RetryOperation.prototype.stop = function() {
   if (this._timeout) {
     clearTimeout(this._timeout);
   }
+  if (this._timer) {
+    clearTimeout(this._timer);
+  }
 
   this._timeouts       = [];
   this._cachedTimeouts = null;
@@ -65,7 +69,7 @@ RetryOperation.prototype.retry = function(err) {
   }
 
   var self = this;
-  var timer = setTimeout(function() {
+  this._timer = setTimeout(function() {
     self._attempts++;
 
     if (self._operationTimeoutCb) {
@@ -82,7 +86,7 @@ RetryOperation.prototype.retry = function(err) {
   }, timeout);
 
   if (this._options.unref) {
-      timer.unref();
+      this._timer.unref();
   }
 
   return true;