generic: test journaling after renaming fsynced file and fsync parent dir

generic: test journaling after renaming fsynced file and fsync parent dir

Test that if we fsync a file, create a directory in the same parent
directory of the file, add a file to the new directory, rename the
initial file and then fsync the parent directory of the first file, after
a power failure the new directory exists, with its new entry and the first
file has the new name and any data we wrote to it before its fsync.

This exercises a reported btrfs bug which is fixed by a patch with the
following subject:

  "btrfs: do not skip logging new dentries when logging a new name"

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>