s4cmd mv -r odd behavior

Hi guys,

I'm not sure what happened when I used `s4cmd mv -r` but I ran the command
```
s4cmd mv -r s3://bucket/folder1 s3://bucket/folder2
```
and now when I run `s4cmd ls s3://bucket/folder2` I see the following
```
DIR s3://bucket/folder2/subdir/
2019-04-10 22:56 0 s3://bucket/folder2/.
2019-04-10 23:08 0 s3://bucket/folder2/subdir
```
And I don't quite understand what's going on now b/c when I ran `s4cmd ls s3://bucket/folder1` before the move I got
```
DIR s3://bucket/folder1/subdir/
2019-02-28 23:01 0 s3://bucket/folder1/
```

This doesn't seem right. Is there something I should have done, and is there someway to recover the old structure?

Start by reproducing the shown `s4cmd mv -r` and `s4cmd ls` commands with the same folder and subdirectory structure. Trace how the recursive move represents directories and determine the expected post-move listing and whether the original structure can be recovered; the issue is done when that behavior is explained or corrected and verified with a focused reproduction.

Written by the indexing model from the issue text.