Don't test for /bin/{dnsdomainname,domainname}, simply try to execute
the command and check if it returned something.
Reported-by: NGlenn Sommer <glemsom@gmail.com>
Acked-by: NWANG Cong <xiyou.wangcong@gmail.com>
Tested-by: NGlenn Sommer <glemsom@gmail.com>
Signed-off-by: NMichal Marek <mmarek@suse.cz>