Set the root password

Very few people (OK, just me at the moment) have this password, as most
will access systems via sudo.  This will only be used for console access
when performing repairs.  The crypted password is stored in the secrets
file -- no need to rely just on crypt(3) for that.

Fixes #3004.
Merge pull request #30 from djmitche/set-root-pw

Set the root password