improve diagnostics on connect and TLS failures

- connect(): include the OS error code/message from stream_socket_client()
  so failures report 'Connection refused', 'Connection timed out', etc.
  instead of the uninformative 'Could not open SMTP Port'.
- starttls(): suppress the misleading PHP warning from
  stream_socket_enable_crypto() (often 'SSL: Success') and append the real
  OpenSSL reason from error_get_last() to the CryptoException.

Author: splitbrain

src/Mailer/SMTP.php

@@ -224,7 +224,10 @@ protected function connect()
             $context
         );
         if (!$this->smtp){
-            throw new SMTPException("Could not open SMTP Port to $host:{$this->port}");
+            throw new SMTPException(
+                "Could not open SMTP Port to $host:{$this->port}" .
+                ($error_message ? " ($error_code: $error_message)" : '')
+            );
         }
         $code = $this->getCode();
         if ($code !== '220'){
@@ -259,8 +262,12 @@ protected function starttls()
             stream_context_set_option($this->smtp, 'ssl', 'allow_self_signed', true);
         }
 
-        if(!\stream_socket_enable_crypto($this->smtp, true, STREAM_CRYPTO_METHOD_ANY_CLIENT)) {
-            throw new CryptoException("Start TLS failed to enable crypto");
+        if(!@\stream_socket_enable_crypto($this->smtp, true, STREAM_CRYPTO_METHOD_ANY_CLIENT)) {
+            $err = error_get_last();
+            throw new CryptoException(
+                "Start TLS failed to enable crypto" .
+                (isset($err['message']) ? ": {$err['message']}" : '')
+            );
         }
         return $this;
     }