Unexpected directory behavior

[nfebe]

During SFTP uploads on the Permanent service, users have reported an unexpected behavior related to directory creation. When using the SFTP command "put -R dir-name" to send a directory that doesn't already exist on Permanent, the first attempt results in an error. After manually creating the directory via the Permanent website, subsequent attempts to upload the same directory result in the creation of duplicate directories with the same name.

This might be related to : #190

Originally reported by @danfuzz

I tried to upload another bunch of files yesterday via SFTP and ran into some trouble which I think is worth
reporting:

● I used the SFTP command "put -R dir-name" (recursively send a directory). On Permanent, the dir- name in question didn't already exist, and the first time I tried the command, I got an error

complaining that the directory didn't exist. A bit odd — because the command should make the
directory — but not terrible, so I went ahead and made the directory via the Permanent website. Then
I retried the command. It worked, but to my surprise it ended up making a new directory with the same
name, so via the web I could see that there were two dir-name directories, one empty, and one with
my uploaded files.

[slifty]

It isn't clear to me where this behavior is coming from. Some possibilities that come to mind:

1. Something to do with how download names are calculated.
2. Some kind of issue with the virtual file system cache (e.g. the folder is created and there's a bug such that the cache does not properly update to include the new folder)