1.9.7 laser compatibility issue

[Kilinich]

In 1.9.7 laser transparency affect ray itself so [1,1,1,0] color laser not working.
I think you must leave old behavior (no alpha channel for laser ray) or add backward compatibility version check.

[emilk]

I'll keep the old behavior instead - in fact, I don't know how, why or when this was changed.