[Samba] mysql backend fix.

[Collen Blijenberg]

Well first, thanx to the samba team for the new release,

here is a little feedback

i just installed it, and it seems that the pdb_sql backend has a little 
flaw, if you upgrade from a earlier version.

there is a new colom, witch will make smaba give an error.
'logon_hours'

in the example database (./examples/pdb/mysq/mysql.dump) this field is 
missing aswell..

dunno why the developers made this extra field, bcoz there was already a 
field for the logon things (logon_div) and i thought unknown_6 was also
part of that (dunno for sure)

annyway, small work around for the mysql backend users:
make an extra field called logon_hours
(logon_hours - int(9)

Thx

Collen