s3:winbindd: Send flags=0 in netr_LogonSamLogon{WithFlags,Ex}()

s3:winbindd: Send flags=0 in netr_LogonSamLogon{WithFlags,Ex}()

These extra flags are an [in,out] argument, so we have to initialize
them to 0. If we pass NETLOGON_SAMLOGON_FLAG_PASS_TO_FOREST_ROOT
or NETLOGON_SAMLOGON_FLAG_PASS_CROSS_FOREST_HOP, a Windows Server
will just return NT_STATUS_NO_SUCH_USER with authoritative=1
(at least if it is itself a DC of the forest root and the requested
 domain is the local domain of the DC).

Pair-Programmed-With: Andreas Schneider <asn@samba.org>

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Andreas Schneider <asn@samba.org>