Repair the RPM database Raw

I had a problem with running a `yum update` on some package. The process
would sleep indefinitely. A clue that something was wrong with the RPM
database (at `/var/lib/rpm`) was that running `rpm -qa` would hang as
well.

The solution is to rebuild the RPM database. In short:

    # Backups!  
    tar -czvf /tmp/rpm.tgz /var/lib/rpm  
      
    # Remove the database locks  
    rm -f /var/lib/rpm/__db*  
      
    # Rebuild!  
    rpm -vv --rebuilddb

That should do it.