tests: only wait for the pid we spawned

In the next patch, we'll introduce an option to allow for leaving zombie
processes in the pid ns for the test so that we can test the behavior of
zombies. Let's not reap everything after restore, since we'll reap the
restored zombies as well.

v2: restore the old behavior when in reap mode

CC: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Acked-by: Andrew Vagin <avagin@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

test/zdtm/lib/ns.c

@@ -343,8 +343,13 @@ int ns_init(int argc, char **argv)
 		kill(pid, SIGTERM);
 
 	ret = 0;
-	while (ret != -1)
-		ret = wait(NULL);
+	if (reap) {
+		while (ret != -1)
+			ret = wait(NULL);
+	} else {
+		waitpid(pid, NULL, 0);
+	}
+
 
 	exit(1);
 }