BUG/MINOR: tools: fix statistical_prng_range()'s output range

This function was added by commit 84ebfabf7 ("MINOR: tools: add
statistical_prng_range() to get a random number over a range") but it
contains a bug on the range, since mul32hi() covers the whole input
range, we must pass it range-1. For now it didn't have any impact, but
if used to find an array's index it will cause trouble.

This should be backported to 2.4.
1 file changed