remove hardcoded connect_timeout

 and add default config for it on HttpClient in TransportManager

src/Illuminate/Mail/Transport/MailgunTransport.php

@@ -75,7 +75,6 @@ public function send(Swift_Mime_Message $message, &$failedRecipients = null)
                 'message' => new PostFile('message', $message->toString()),
             ];
         }
-        $options['connect_timeout'] = 60;
 
         return $this->client->post($this->url, $options);
     }

src/Illuminate/Mail/Transport/MandrillTransport.php

@@ -53,7 +53,6 @@ public function send(Swift_Mime_Message $message, &$failedRecipients = null)
         } else {
             $options = ['body' => $data];
         }
-        $options['connect_timeout'] = 60;
 
         return $this->client->post('https://mandrillapp.com/api/1.0/messages/send-raw.json', $options);
     }

src/Illuminate/Mail/Transport/SparkPostTransport.php

@@ -47,7 +47,6 @@ public function send(Swift_Mime_Message $message, &$failedRecipients = null)
         $message->setBcc([]);
 
         $options = [
-            'connect_timeout' => 60,
             'headers' => [
                 'Authorization' => $this->key,
             ],

src/Illuminate/Mail/TransportManager.php

@@ -101,7 +101,7 @@ protected function createMailgunDriver()
         $config = $this->app['config']->get('services.mailgun', []);
 
         return new MailgunTransport(
-            new HttpClient(Arr::get($config, 'guzzle', [])),
+            $this->getHttpClient($config),
             $config['secret'], $config['domain']
         );
     }
@@ -116,7 +116,7 @@ protected function createMandrillDriver()
         $config = $this->app['config']->get('services.mandrill', []);
 
         return new MandrillTransport(
-            new HttpClient(Arr::get($config, 'guzzle', [])), $config['secret']
+            $this->getHttpClient($config), $config['secret']
         );
     }
 
@@ -130,7 +130,7 @@ protected function createSparkPostDriver()
         $config = $this->app['config']->get('services.sparkpost', []);
 
         return new SparkPostTransport(
-            new HttpClient(Arr::get($config, 'guzzle', [])), $config['secret']
+            $this->getHttpClient($config), $config['secret']
         );
     }
 
@@ -164,4 +164,19 @@ public function setDefaultDriver($name)
     {
         $this->app['config']['mail.driver'] = $name;
     }
+
+    /**
+     * get configured http client
+     * @param $config
+     * @return HttpClient
+     */
+    protected function getHttpClient($config)
+    {
+        $guzzleConfig = Arr::get($config, 'guzzle', []);
+
+        // add default config for timeout
+        $guzzleConfig = Arr::add($guzzleConfig, 'connect_timeout', 60);
+
+        return new HttpClient($guzzleConfig);
+    }
 }