get_analysis and analysis_modules with instances is confusing

[unixfreak0037]

If you're dealing with an analysis module that is using "instances",
then instead of this

analysis = observable.get_analysis(self.generated_analysis_type)

you have to do this

analysis = observable.get_analysis(self.generated_analysis_type, instance=self.instance)

That should be taken care of in behind the scenes instead of forcing the developer to figure that out.