Replaces uses of `sys.maxint` w `sys.maxsize` in trim()
Replaces uses of `sys.maxint` w `sys.maxsize` in trim()

These would cause AttributeErrors in Python 3.x.

In Python 3.x the `int` have no min or max, hence `sys.maxint` was removed.

https://www.python.org/dev/peps/pep-0237/

Yubico/python-yubicommon,moreati/python-yubicommon