ScpClient: Upload(Stream, String) does not throw exception when parent directory does not exist

[drieseng]

When you specify a (remote) file path to Upload(Stream, String) for which the last part of the directory directory (parent path) does not exist, then we currently do not throw an exception.

Instead the file is created with as path the directory of specified path.

For example:
If the directory /home/sshnet exists, but directory /home/sshnet/logs does not exist, then using the Upload(Stream, String) method to upload the content to the /home/sshnet/logs/file path will actually upload the content to the file path /home/sshnet/logs.