s3 winbind auth_log: Tests for logon id logging.

s3 winbind auth_log: Tests for logon id logging.

Tests to validate that winbind generates a random logon_id and passes it
in the netlogon call.

This will allow the linking of the windbind authentication requests and
the SamLogon request on the DC.

Signed-off-by: Gary Lockyer <gary@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>