selinux: fix a possible memory leak in cond_read_node()

The cond_read_node() should free the given node on error path as it's
not linked to p->cond_list yet.  This is done via cond_node_destroy()
but it's not called when next_entry() fails before the expr loop.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Paul Moore <pmoore@redhat.com>

security/selinux/ss/conditional.c

@@ -404,7 +404,7 @@ static int cond_read_node(struct policydb *p, struct cond_node *node, void *fp)
 
 	rc = next_entry(buf, fp, sizeof(u32) * 2);
 	if (rc)
-		return rc;
+		goto err;
 
 	node->cur_state = le32_to_cpu(buf[0]);