This commit is the result of the squash of the following main commits:

Author: Radosław Korzeniewski <radekk@inteos.pl>
Date:   Tue Nov 19 19:47:35 2019 +0100

    k8s: Update regression tests preparation.

Author: Alain Spineux <alain@baculasystems.com>
Date:   Tue Oct 23 11:17:55 2018 +0200

    regress: win32 misc

    - new sed @win32_wsep_file@, this is win32_file, but with Windows
      separators:  win32_file="c:/tmp" -> win32_wsep_file="c:\\tmp"

Author: Radoslaw Korzeniewski <radekk@inteos.pl>
Date:   Mon Dec 4 17:12:08 2017 +0100

    regress: Add swift plugin regression tests using backend and Swift store.

Author: Eric Bollengier <eric@baculasystems.com>
Date:   Fri Nov 14 15:13:05 2014 +0100

    regress: Add test for kvm plugin