Backupfixes - add the -sse option and fix the mysql_backup script

In detail, this adds the --sse option - I have tested this and it has run ok in an overnight cronjob.
It also fixes the mysql backup script, by adding a -h option to part of the script, as it was failing on that.  It also removes the -u option as we want to pick that up from my.cnf and not from the script itself.  This also makes it a bit more portable.  I have run this script from the command line and it works fine.  I've updated the server with this script so we'll see tomorrow if it's worked ok.