Fixed coding standard violations in the Framework\Filesystem namespac…

…e, so that it will be checked bij PHP CS and no longer be ignored while doing CI checks. Made the following changes:

- Removed @codingStandardsIgnoreFile
- Fixed number of chars per line
- Removed the is_null function in order to do a normal compare.

lib/internal/Magento/Framework/Filesystem/Io/Sftp.php

@@ -4,8 +4,6 @@
  * See COPYING.txt for license details.
  */
 
-// @codingStandardsIgnoreFile
-
 namespace Magento\Framework\Filesystem\Io;
 
 /**
@@ -16,7 +14,6 @@
 class Sftp extends AbstractIo
 {
     const REMOTE_TIMEOUT = 10;
-
     const SSH2_PORT = 22;
 
     /**
@@ -48,7 +45,9 @@ public function open(array $args = [])
         }
         $this->_connection = new \phpseclib\Net\SFTP($host, $port, $args['timeout']);
         if (!$this->_connection->login($args['username'], $args['password'])) {
-            throw new \Exception(sprintf("Unable to open SFTP connection as %s@%s", $args['username'], $args['host']));
+            throw new \Exception(
+                sprintf("Unable to open SFTP connection as %s@%s", $args['username'], $args['host'])
+            );
         }
     }
 
@@ -168,7 +167,7 @@ public function cd($dir)
      */
     public function read($filename, $destination = null)
     {
-        if (is_null($destination)) {
+        if ($destination === null) {
             $destination = false;
         }
         return $this->_connection->get($filename, $destination);