Typo in hash function

[aimfiz]

Hi George, I just noticed that when the symbol hash function was changed, a stray "+" was left in before the "=", which makes the multiplier not the intended 67 (prime) but instead 68 (4*17), which makes all symbols of the same length and the same last 16 characters hash to the same value (if longs are only 32 bits). Zapping that plus should improve things for pathological users.