btrfs: test incremental send after renaming and linking file

btrfs: test incremental send after renaming and linking file

Test that an incremental send operation works correctly when an inode A
is renamed, a new hard link added to it and some other inode B is renamed
to the old name of inode A.

The btrfs bug is fixed by the following patch for the linux kernel:

  "Btrfs: send, fix invalid path after renaming and linking file"

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>