Usage of `fakeroot` crashes patool

Steps to reproduce:
```
$ tar -cvf install.tar install.py
$ ./fact_extractor/fact_extract.py -d  install.tar
```
Looking at `/tmp/extractor/reports/meta.json` it can be observed that patool calls `/usr/bin/file --brief --mime-type install.tar`
which causes the crash when run with `fakeroot`.

This is not an issue in the docker container as it already runs with root.