MAGETWO-86777: setup:di:compile fatal error for Zend\Mail\Message

- Add alias to conflicting Zend\Mail\Message import

Author: tjwiebell

lib/internal/Magento/Framework/Mail/Transport.php

@@ -7,7 +7,7 @@
 
 use Magento\Framework\Exception\MailException;
 use Magento\Framework\Phrase;
-use Zend\Mail\Message;
+use Zend\Mail\Message as ZendMessage;
 use Zend\Mail\Transport\Sendmail;
 
 class Transport implements \Magento\Framework\Mail\TransportInterface
@@ -39,7 +39,7 @@ public function sendMessage()
     {
         try {
             $this->zendTransport->send(
-                Message::fromString($this->message->getRawMessage())
+                ZendMessage::fromString($this->message->getRawMessage())
             );
         } catch (\Exception $e) {
             throw new MailException(new Phrase($e->getMessage()), $e);