CVE-2016-2110: winbindd: add new_spnego to the WINBINDD_CCACHE_NTLMAUTH response

CVE-2016-2110: winbindd: add new_spnego to the WINBINDD_CCACHE_NTLMAUTH response

We don't need to change the protocol version because:

1. An old client may provide the "initial_blob"
   (which was and is still ignored when going
   via the wbcCredentialCache() function)
   and the new winbindd won't use new_spnego.

2. A new client will just get a zero byte
   from an old winbindd. As it uses talloc_zero() to
   create struct winbindd_response.

3. Changing the version number would introduce problems
   with backports to older Samba versions.

New clients which are capable of using the new_spnego field
will use "negotiate_blob" instead of "initial_blob".

BUG: https://bugzilla.samba.org/show_bug.cgi?id=11644

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Günther Deschner <gd@samba.org>