New argument to refresh keyring on demand

check.py

@@ -208,6 +208,9 @@ if __name__ == '__main__':
     import argparse
     parser = argparse.ArgumentParser()
 
+    parser.add_argument("-R", "--refresh-keys", action="store_true",
+                        help="refresh GnuPG keyring")
+
     parser.add_argument("-s", "--sign", action="store_true",
                         help="limit check to signature")
 
@@ -243,6 +246,9 @@ if __name__ == '__main__':
 
     args = parser.parse_args()
 
+    if args.refresh_keys:
+        subprocess.Popen(["gpg", "--homedir=" + GNUPG_DIRECTORY, "--batch", "--refresh-keys"])
+
     if not args.skip_max_submission:
         with subprocess.Popen(["date", "-d", args.soft_max_submission, "-u", "-Iseconds"], stdout=subprocess.PIPE) as f:
             SOFT_MAX_SUBMISSION = datetime.strptime(f.stdout.read().strip().decode().replace(":", ""), "%Y-%m-%dT%H%M%S%z")