Bug #6523: various problems with jobsub_submit.py
dropbox storage area has lots of unnecessary duplicate files in oddly named directories
the dropbox storage area has lots of unnecessary duplicate files in oddly named directories. Potential for lots of unnecessary uploading to the server, and a operational headache when the dropbox area fills up with duplicates. The dropbox area should have subdirectories named after a hex digest of the uploaded file, if file already lives on dropbox server don't upload it again. This has the added benefit of ensuring that the file was not corrupted when uploaded by checking clients digest against servers digest.