util: Make set_proc_fd report success/error only

Returning the new proc fd value is useless.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cr-dump.c

@@ -1274,14 +1274,11 @@ static int fill_zombies_pids(struct pstree_item *item)
 static int dump_zombies(void)
 {
 	struct pstree_item *item;
-	int oldfd, ret = -1;
+	int ret = -1;
 	int pidns = current_ns_mask & CLONE_NEWPID;
 
-	if (pidns) {
-		oldfd = set_proc_fd(pidns_proc);
-		if (oldfd < 0)
-			return -1;
-	}
+	if (pidns && set_proc_fd(pidns_proc))
+		return -1;
 
 	for_each_pstree_item(item) {
 		if (item->state != TASK_DEAD)

util.c

@@ -179,7 +179,9 @@ void close_proc()
 
 int set_proc_fd(int fd)
 {
-	return install_service_fd(PROC_FD_OFF, fd);
+	if (install_service_fd(PROC_FD_OFF, fd) < 0)
+		return -1;
+	return 0;
 }
 
 int set_proc_mountpoint(char *path)