Both are good for building a career and have immense number of opportunities. Every corporate body needs both human resource manager and international business manager. But both their requirements are lesser than that of other branches like Finance or marketing. 

If you have an inclination towards any of these branches then you should go for it. But if you have no such preferences then go for HR because many indian companies or startups who don't have much foreign interactions don't require an IB personnel. 

Good luck