vp-upload . should infer the right filenames

[Zaharid]

I was trying to upload a PDF from the folder I was in and got

$ vp-upload .
[INFO]: Detected pdf input
[INFO]: Checking SSH connection to [email protected].
[INFO]: Connection seems OK.
[ERROR]: A pdf with the same name already exists on the server. To overwrite it use the --force flag, as in `vp-upload <pdf_name> --force.
Traceback (most recent call last):
  File "/home/zah/anaconda3/bin/vp-upload", line 33, in <module>
    sys.exit(load_entry_point('validphys', 'console_scripts', 'vp-upload')())
  File "/home/zah/nngit/nnpdf/validphys2/src/validphys/scripts/vp_upload.py", line 80, in main
    pass
  File "/home/zah/anaconda3/lib/python3.8/contextlib.py", line 120, in __exit__
    next(self.gen)
  File "/home/zah/nngit/nnpdf/validphys2/src/validphys/uploadutils.py", line 249, in upload_or_exit_context
    yield
  File "/home/zah/anaconda3/lib/python3.8/contextlib.py", line 120, in __exit__
    next(self.gen)
  File "/home/zah/nngit/nnpdf/validphys2/src/validphys/uploadutils.py", line 242, in upload_context
    res = self.upload_output(output_path, force)
  File "/home/zah/nngit/nnpdf/validphys2/src/validphys/uploadutils.py", line 227, in upload_output
    raise UploadError
validphys.uploadutils.UploadError

That PDF didn't exist, and if I had followed the suggestion and used --force that would presumably have had overwritten . which is a terrible idea.

We should both resolve the folder name as well as possible (i.e. from the absolute path) and print what the conflicting name is.