the compiler suggested braces around the conditions, and by look of
it, it was right: these asserts most likely want express that only the
threephase case or the twophase case without gas are handled...
this changes the conversion of the results to hopefully make it work
with twophase simulations. Note that flow_ebos still does not work
because there is a crash in the well model that I don't understand
(and also, I've disabled an assertation in the well model plus I'm not
completely sure if the conversion code need to do something about the
primary variables in the twophase case).
