r610: - Merge the Samba3 'ntlm_auth --diagnostics' testsuite to Samba4.

r610:  - Merge the Samba3 'ntlm_auth --diagnostics' testsuite to Samba4.
  - This required using NETLOGON_NEG_AUTH2_FLAGS for the
    SetupCredentials2 negotiation flags, which is what Samba3 does,
    because otherwise the server uses different crypto.
  - This tests the returned session keys, which we decrypt.

 - Update the Samba4 notion of a 'session key' to be a DATA_BLOB in
   most places.

 - Fix session key code to return NT_STATUS_NO_SESSION_KEY if none is
   available.

 - Remove a useless argument to SMBsesskeygen_ntv1

 - move netr_CredentialState from the .idl to the new credentials.h

Andrew Bartlett
(This used to be commit 44f8b5b53e6abd4de8a676f78d729988fadff320)