Part of a wider housekeeping effort on the packages repository.

Signed-off-by: Alberto Bursi <alberto.bursi@outlook.it>

We were copying a wrapper script instead of the actual executable.

Fixes #2910

Signed-off-by: Florian Fainelli <florian@openwrt.org>

stoken is a tokencode generator compatible with RSA SecurID
128-bit (AES). stoken supports libtomcrypt and libnettle, we build
against nettle by default since tomcrypt is not packaged by OpenWrt

Signed-off-by: Florian Fainelli <florian@openwrt.org>