rm _del_ as it might leak memory
renamed to tmp file cleanup
added exception handling when traversing file list, even if one fails try rest
added cleanup to finally to ensure removal in most cases
- get_real_file will decrypt vault encrypted files and return a path to
a temporary file.
- cleanup_real_file will remove a temporary file created previously with
get_real_file
Note that this will break if we deal with non-utf8 paths. Fixing this
way because converting everythig to byte strings instead is a very
invasive task so it should be done as a specific feature to provide
support for non-utf8 paths at some point in the future (if needed).