network/tcp_cmds/finger: fix finger bad user and host test

Finger always return 0 with bad user and host test. And it also return
different error message on different distros. So let's only check stderr
message and decide whether the test pass or fail.

Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Acked-by: Cyril Hrubis <chrubis@suse.cz>
1 file changed