tools/pyboard.py: Use slice del instead of list.clear() for Py2 compat.
Python 2 does not have list.clear().
@@ -567,7 +567,7 @@ def main():
# do filesystem commands, if given
if args.filesystem:
filesystem_command(pyb, args.files)
- args.files.clear()
+ del args.files[:]
# run the command, if given
if args.command is not None:
