Mirror penalities are floats while they're intended to be integers

[David Smid]

This code in mirror.py should perform floor division but does not:

                # Integer division by granularity ensures that mirrors
                # which are close enough will be considered equal to
                # distribute load.
                penality /= GRANULARITY

penality is a float, thus the result is float as well.
Since Python 2.2, there's a new operator // that does floor division regardless of operands type:

                penality //= GRANULARITY

See http://www.python.org/dev/peps/pep-0238/