r2071: - change smbtorture to use the popt_common stuff

r2071: - change smbtorture to use the popt_common stuff
  this means -U DOM\\user is know allowed

- torture:userdomain is a new smb.conf parameter
  because lp_workgroup is not the domain of the user

- we use torture:userdomain now in the tests instad of lp_workgroup

- for backward compat the userdomain is lp_workgroup() by default and
  not lp_netbios_name(), which my change later to match 'net' and 'smbclient'..

- we now have dublicate options e.g. -N -s ...
  tridge: can we change this?

metze