tests: remove dependency on base64

tests: remove dependency on base64

Triggered by the report from Ilya, that if base64 is missing, the tests
would still report success:

  Testing tls-crypt-v2 key generation (max length
metadata)..../t_lpback.sh: base64: not found
  OK
  PASS: t_lpback.sh

The easiest way to fix that, is to remove the dependency on base64 (which
is it's current form wouldn't work on OSX anyway, because their base64
doesn't understand "-w0").

Signed-off-by: Steffan Karger <steffan.karger@fox-it.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <E1hON0G-0007yB-3H@sfs-ml-4.v29.lw.sourceforge.com>
URL: https://www.mail-archive.com/search?l=mid&q=E1hON0G-0007yB-3H@sfs-ml-4.v29.lw.sourceforge.com
Signed-off-by: Gert Doering <gert@greenie.muc.de>