CVE-2016-2115: s3:libsmb: let SMB_SIGNING_IPC_DEFAULT use "client ipc min/max protocol"

CVE-2016-2115: s3:libsmb: let SMB_SIGNING_IPC_DEFAULT use "client ipc min/max protocol"

We need NT1 => LATEST in order to work against all servers which support
DCERPC over ncacn_np.

This is a mini step in using SMB2/3 in our client side by default.

This gives us a higher chance that SMB signing is supported by the
server (as it can't be turned off for SMB2 and higher).

BUG: https://bugzilla.samba.org/show_bug.cgi?id=11756

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>