Use constant time memcmp when comparing HMACs in openvpn_decrypt.

Signed-off-by: Steffan Karger <steffan.karger@fox-it.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
Signed-off-by: Gert Doering <gert@greenie.muc.de>
free_ssl_lib (void)
{
  crypto_uninit_lib ();
  prng_uninit();
}

free_ssl_lib (void)
{
  crypto_uninit_lib ();
  prng_uninit();
}
