Cannot list or remove specific index entries unless they exist on the file system

[tdilauro]

fixi verifies the presence of the specified path before initializing the index instance. It is useful and, in some cases, important to be able to interrogate or purge entries in the absence of a file system analog. For example, if a file is being moved, it is sensible to be able to both list its original fixity attributes (ls -v) and to remove its entry (rm).