smb3: display security information in /proc/fs/cifs/DebugData more accurately

When the server required encryption (but we didn't connect to it with the
"seal" mount option) we weren't displaying in /proc/fs/cifs/DebugData that
the tcon for that share was encrypted. Similarly we were not displaying
that signing was required when ses->sign was enabled (we only
checked ses->server->sign).  This makes it easier to debug when in
fact the connection is signed (or sealed), whether for performance
or security questions.

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>