block: Add reopen_queue to bdrv_child_perm()

In the context of bdrv_reopen(), we'll have to look at the state of the
graph as it will be after the reopen. This interface addition is in
preparation for the change.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
diff --git a/block/mirror.c b/block/mirror.c
index 6531652..6f5cb9f 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -1084,6 +1084,7 @@
 
 static void bdrv_mirror_top_child_perm(BlockDriverState *bs, BdrvChild *c,
                                        const BdrvChildRole *role,
+                                       BlockReopenQueue *reopen_queue,
                                        uint64_t perm, uint64_t shared,
                                        uint64_t *nperm, uint64_t *nshared)
 {