Bug 1883: Directory reading cannot be cancelled for SFTP servers that provide optional end-of-list field

https://winscp.net/tracker/1883

Source commit: 579caa7b06f68b10fb532ad5e83b7b5934741802

source/core/SftpFileSystem.cpp

@@ -3489,7 +3489,8 @@ void __fastcall TSFTPFileSystem::ReadDirectory(TRemoteFileList * FileList)
           }
         }
 
-        if ((FVersion >= 6) &&
+        if (!isEOF &&
+            (FVersion >= 6) &&
             // As of 7.0.9 the Cerberus SFTP server always sets the end-of-list to true.
             // Fixed in 7.0.10.
             (FSecureShell->SshImplementation != sshiCerberus) &&