inetutils: add dnsdomainname to ALTERNATIVE

The dnsdomainname can also be provided by busybox and net-tools. Also
move it from ${bindir} to ${base_bindir} because the command provided by
busybox or net-tools is located here.

Signed-off-by: Yi Zhao <yi.zhao@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>