SizingParameters does not work in ruby

[muh182]

@kbenne this is the bug report for the SizingParameters error message that we've looked at it together:

sizingParameters=model.getSizingParameters

Shows this error:

The corresponding line is:
https://github.com/NREL/OpenStudio/blob/develop/openstudiocore/src/model/ModelSimulation.i#L33

FYI @macumber

[macumber]

Looks like this should be SWIG'd as a unique model object, thanks for the find Mohammad!