s3-rpc_server read and write the unix_token and unix_info across named_pipe_auth

s3-rpc_server read and write the unix_token and unix_info across named_pipe_auth

This ensures that the exact same token is used on both sides of the
pipe, when a full token is passed (ie, source3 to source3, but not yet
source4 to to source3 as the unix info isn't calculated there yet).

If we do not have unix_token, we fall back to the old behaviour and go
via create_local_token().  (However, in this case the security_token
is now overwritten, as it is better to have it match the rest of the
session_info create_local_token() builds).

Andrew Bartlett

Signed-off-by: Andrew Tridgell <tridge@samba.org>