Reorder Check results

At this time Check.result may take a value in [0,1,2,3,4,5]

The value 2 was used when gaps were presents in streams. Checks were stopping here.

Now, even if a stream contains gaps, we continue the check processing and try to remove instrumental response after merging the traces in the stream. So we do not need this result = 2 anymore.

So let's get rid of it