hangs after Removing temporary files...done

### Description

scancode hangs after printing the "Removing temporary files...done" message.

### How To Reproduce

scancode -clpeui -n 1 --verbose --json-pp spdx.json rpmbuild

### Output

Save scan results...
Save scan results as: json-pp...
Scanning done.
Summary: info, licenses, copyrights, packages, emails, urls with 1 process(es)
Errors count: 0
Scan Speed: 0.75 files/sec. 267.11 KB/sec.
Initial counts: 3112 resource(s): 3109 file(s) and 3 directorie(s)
Final counts: 3112 resource(s): 3109 file(s) and 3 directorie(s) for 1.06 GB
Timings:
scan_start: 2022-06-17T152132.712940
scan_end: 2022-06-17T163040.349675
setup_scan:licenses: 2.57s
setup: 2.58s
inventory: 0.64s
scan:packages: 0.97s
scan: 4143.55s
output:json-pp: 10.11s
output: 10.11s
total: 4157.92s
Removing temporary files...done.
WARNING: Outdated ScanCode Toolkit version! You are using an outdated version of ScanCode Toolkit: 30.1.0 released on: 2021-09-24. A new version is available with important improvements including bug and security fixes, updated license, copyright and package detection, and improved scanning accuracy. Please download and install the latest version of ScanCode. Visit https://github.com/nexB/scancode-toolkit/releases for details.

### System configuration

SLES 15 SP3
git clone https://github.com/nexB/scancode-toolkit.git; ./configure; pip install scancode-toolkit
ScanCode version 30.1.0
ScanCode Output Format version 1.0.0
SPDX License list version 3.14