Some non-GSSAPI implementations that instead try to create compatible packets by wrapping krb5_mk_req()
can trigger a NULL authenticator here. Assume this to be equvilent to specifying an all-zero
channel bindings and some reasonable (fixed) flags.
Original patch by Andrew Bartlett, restructured by Douglas Bagnall
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>