data file path changing by shipment

[njakuschona]

After shipping the ERC to, for example, Zenodo, all important files (e.g. display.html) are moved by the shipper. The files are then stored under id/data/data/display.html instead of id/data/display.html.

[nuest]

@NJaku01 Note that a path id/data/data is not what we want.

If the ERC is already a bag (which by definition it is, otherwise it is a workspace), then we need to make sure that the shipper updates but not recreates the bag.

If there is a data directory, but there is no bagit.txt, then the path id/data/data/display.html could be correct. Please be sure to keep the paths in the erc.yml in sync with the values in the database.