btrfs: test incremental send after replacing directory with a file

btrfs: test incremental send after replacing directory with a file

Test that an incremental send/receive operation works correctly after
moving some directory inode A, renaming a regular file inode B into the
old name of inode A and finally creating a new hard link for inode B at
directory inode A.

This issue is fixed by the following patch for the linux kernel:

  "Btrfs: incremental send, fix invalid path for link commands"

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