s3:rpc_server:netlogon: don't require NEG_AUTHENTICATED_RPC in netr_ServerAuthenticate*()

s3:rpc_server:netlogon: don't require NEG_AUTHENTICATED_RPC in netr_ServerAuthenticate*()

The domain join with VMWare Horizon Quickprep seems to use
netr_ServerAuthenticate3() with just the NEG_STRONG_KEYS
(and in addition the NEG_SUPPORTS_AES) just to verify a password.

Note: NETLOGON_NEG_SCHANNEL is an alias to NEG_AUTHENTICATED_RPC.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13464 (maybe)
BUG: https://bugzilla.samba.org/show_bug.cgi?id=13949

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