inetutils: use new update-alternatives syntax

Correct the usage of alternative link and target:
ALTERNATIVE_LINK_NAME[name] = "target"
ALTERNATIVE_TARGET[name] = "target"

Signed-off-by: Li Wang <li.wang@windriver.com>
Signed-off-by: Jackie Huang <jackie.huang@windriver.com>
Signed-off-by: Joe MacDonald <joe@deserted.net>