The name yielded no signs of recognition. Katniss wasn't Katniss at the moment and Gollum certainly hadn't bother to learn her name when he was taking over her body. It was of no consequence to him. He had little time for anything but finding the thing he most longed for.
"Where is it?" he hissed at the shopkeeper using the girl's voice. Her body was delightfully fit. He was sure he could do quite a bit of damage. The shopkeeper WOULD yield and tell him what he wanted to know and the voice shouting someone else's name at him was nothing more than a mild annoyance, so Gollum ignored it, continuing to advance on his target.