Running a component with an existing sample_component db entry, causes a crash

[kriskiil]

Something is not handled properly in datahandling.BifrostObject.load(), which causes bifrost to crash with a NoneType has no .json method or property or something, in case of an existing sample_component entry in mongodb.

The impact is that Bifrost crashes in an opaque way if the database is not cleaned up before rerunning samples. This should be handled in some way.