Failure to cleanup Aquatone files

[0xdade]

In some situations, such as below when the process gets killed, we fail to cleanup the aquatone directory for some reason that I haven't noticed before.

[!] (3ud7hcwtnz) Killing slacker process
[!] Thread-2: Failed to acquire HTTPS screenshot for 178.128.187.177
[+] Thread-2: Cleaning up files for 3ud7hcwtnz
Exception in thread Thread-2:
Traceback (most recent call last):
  File "/usr/lib/python3.7/threading.py", line 917, in _bootstrap_inner
    self.run()
  File "./natlas-agent.py", line 359, in run
    result = scan(target_data)
  File "./natlas-agent.py", line 335, in scan
    cleanup_files(scan_id)
  File "./natlas-agent.py", line 181, in cleanup_files
    os.remove(file)
IsADirectoryError: [Errno 21] Is a directory: 'data/aquatone.3ud7hcwtnz.https'

[0xdade]

[+] Thread-1: Fetching Target from https://natlas.io
[+] Thread-1: [Server] Target: 91.58.21.142
[+] Thread-1: Scan an0z6nauq27xiw4i Complete
Exception in thread Thread-1:
Traceback (most recent call last):
  File "/usr/lib/python3.6/threading.py", line 916, in _bootstrap_inner
    self.run()
  File "./natlas-agent.py", line 365, in run
    result = scan(target_data)
  File "./natlas-agent.py", line 322, in scan
    shutil.rmtree("data/aquatone.%s" % scan_id)
  File "/opt/natlas/natlas-agent/venv/lib/python3.6/shutil.py", line 477, in rmtree
    onerror(os.lstat, path, sys.exc_info())
  File "/opt/natlas/natlas-agent/venv/lib/python3.6/shutil.py", line 475, in rmtree
    orig_st = os.lstat(path)
FileNotFoundError: [Errno 2] No such file or directory: 'data/aquatone.an0z6nauq27xiw4i'

Another example