Particles 3D initial velocity always random

[maxim-sheronov]

Operating system or device - Godot version:
Arch linux, Godot 3.0 - last build from master branch

Issue description:
If I set initial velocity for particles to 1, and velocity random to 0, as I understant, particles' velocity should be constant 1.
But it is random from 0 to 1. And changing of "velocity random" does not make any effect.

[reduz]

I try to see if i can reproduce but it seems to work well. I think someone might have fixed this recently in a PR. The current code looks ok, so closing this issue.