fixes #3241 - default password is now MD5

I am changing the default password to "$1$default$hCkak1kaJPQILNmYbUXhD0".
Can you plese test this on various systems (Debian, Ubuntu, Fedora, Suse)?
The only thing to do is to provision a system with default root password set
to this and try to log in.

I don't know why the current default password (plain crypt with "xy" salt)
does not work with Anaconda in RHEL6.

We can implement auto-encryption of user-inserted password for this entry,
but I am not going to do this in this PR as I would like to get RHEL working
in 1.3 final release. Please do comment and test.