Fix the password issue on console/sshd

[pdostal]

This is fix of an issue discovered on Live systems, where root password is empty.
I use custom password for the sshboy user and cp instead of scp.

• Related ticket: poo#44696
• Needles: No need
• Verification run: Tumbleweed@GNOME-Live

This was discovered in #6295 by @DimStar77

[pdostal]

I implemented install instead of cp; chmod; chown as suggested by @dzedro (thank you) and it's already green on SLE12SP4 and pending on Tumbleweed@GNOME-Live.

[OleksandrOrlov]

Hi @pdostal, Could you please take a look, as one of the tests is failed on SLE15. Seems like opensusebasetest::select_serial_terminal(); is not implemented for 'svirt' backend.

[OleksandrOrlov]

@pdostal, It also failed on s390x on different step. Would you like to revert both #6295 and #6351, so that you'll be able to fix all the issues and verify them without hurry?

[pdostal]

@OleksandrOrlov preferably no. I was reminded in poo#44696 as well. Thank you for merging - we fixed the password problem with Live distributions. Now I will continue with the opensusebasetest::select_serial_terminal() on the svirt backend. I hope one day will be enough.