Remove unused parsedmarc.utils.tempdir (#517)

Parsedmarc.utils was creating a temp directory on every import, but this directory is no longer used anywhere.

parsedmarc/utils.py

@@ -13,7 +13,6 @@ import mailparser
 import json
 import hashlib
 import base64
-import atexit
 import mailbox
 import re
 import csv
@@ -45,16 +44,6 @@ null_file = open(os.devnull, "w")
 mailparser_logger = logging.getLogger("mailparser")
 mailparser_logger.setLevel(logging.CRITICAL)
 
-tempdir = tempfile.mkdtemp()
-
-
-def _cleanup():
-    """Remove temporary files"""
-    shutil.rmtree(tempdir)
-
-
-atexit.register(_cleanup)
-
 
 class EmailParserError(RuntimeError):
     """Raised when an error parsing the email occurs"""