Added code that will cause the ComputeAndAdjustRegionParameters to
return an empty dataset when it is first called. ComputeAndAdjustParameters
is first called in GetInformation (if we are in demand-driven mode).
At this point, the user has not requested a region and hence N becomes 2.
In order, to get the correct value of N and proper behavior, the user had to
change the number of samples in the GUI, e.g., say to 5 and then change it
back to 10. Thereafter the filter would work as expected. This commit will
cause the filter to essentially ignore the first time it is being called.