Fix memory leak in CaloHypo

The m_position behaves as an owned resource, but was only deallocated in the destructor and not when overwritten by setPosition.

As a bonus, remove the extraneous setPosition in CaloHypo::clone. The copy constructor copies the m_position member anyway.

This is the fix for the memory growth observed in the Tesla validation production: https://lblogbook.cern.ch/Operations/27129