random: fix random logic with getrandom

random: fix random logic with getrandom

The older random functions returned random values in the range of
0 - RAND_MAX. This is what the http randomize code was expecting.

Newer methods, based on getrandom (or probably Windows too), return
a much large range of values, including negative values and >RAND_MAX.

This patch adds a wrapper to turn the returned value into the expected
range before using it in the http code.

The same is true for the stream engine.