Allow tar::File to set the file path

[ghost]

I'm porting some code that uses libarchive to Rust and there is a need to replicate the function archive_set_entry_pathname(), which sets the archive entry path to the specified string in C. The entry is like the tar::File while iterating, except I think it's a pointer to the current header of the archive iterator. Being able to change the tar::File's path should accomplish this.

Please refer to the following man pages for more information:
man archive_entry
man archive_entry_paths

[ghost]

Not needed anymore. To solve this problem, just use a HashSet to hold all the tar::File paths through one iteration and manipulate those paths as needed for another operation.