fix memory leak in calloc_packet_info

memory leak would happen when multiple parse_packet
was called on the same buffer.
fix memory leak in calloc_packet_info

memory leak would happen when multiple parse_packet
was called on the same buffer.
Merge branch 'packet_info_memleak' of https://github.com/iHiroakiKawai/trema-edge into packet_info_memleak
Merge pull request #58 from iHiroakiKawai/packet_info_memleak

fix memory leak in calloc_packet_info