remove unused argument, fix pylint warnings

qmprebase

@@ -17,9 +17,6 @@ from libqmpbackup import version
 from libqmpbackup.lib import QmpBackup
 
 parser = argparse.ArgumentParser(prog=sys.argv[0])
-parser.add_argument(
-    "--debug", dest="debug", help="activate debug log", action="store_true", required=0
-)
 subparsers = parser.add_subparsers(help="sub-command help")
 parser_rebase = subparsers.add_parser("rebase", help="rebase")
 parser_rebase.set_defaults(which="rebase")
@@ -41,17 +38,16 @@ parser_rebase.add_argument(
 argv = parser.parse_args()
 try:
     action = argv.which
-except Exception:
+except AttributeError:
     parser.print_help()
     sys.exit(1)
 
-common = QmpBackup(argv.debug)
+common = QmpBackup(False)
 log = common.setup_log()
 
 log.info("Version: %s Arguments: %s", version.VERSION, " ".join(sys.argv))
 
 if action == "rebase":
-    """Rebase images in directory"""
     if common.rebase(argv.dir, argv.dry_run, argv.until):
         log.info("Image files rollback successful.")
         sys.exit(0)