Better emulation of old scp behavior

[beldmit]

When we use scp in SFTP mode, we try to create a non-existent directory
to better emulate the old SCP behavior

[beldmit]

Red Hat Enterprise Linux 8 series is based on OpenSSH 8.0, which is rather old.

Soon after the OpenSSH 8.0 was published, the upstream introduced a server-side fix for sftp, which changes the use of POSIX realpath (on LInux) to the OpenBSD one with various quirks:
569b650

If the OpenBSD realpath is in use on the server, the current master successfully copies directories using scp in SFTP mode. Otherwise problems occur.

As RHEL 8 series will definitely be in wide use for several more years, I kindly ask the OpenSSH upstream to consider this patch, which is trying to workaround the server side on the client side.