phoenix/starter_kit: broken is_odd

[olafvdspek@…]

is_odd is broken for negative ints.

[Steven Watanabe]

Details:

From 5.6 "If both operands are nonnegative then the remainder is nonnegative; if not, the sign of the remainder is implementation-defined."

The implementation is

bool
is_odd(int arg1)
{
    return arg1 % 2 == 1;
}

The correct test is

bool
is_odd(int arg1)
{
    return arg1 % 2 != 0;
}

[Joel de Guzman]

fixed