refetch the packet_info address

push_vlan_tag might change the packet_info address, so
we must refetch the address.
fix typo
refetch the packet_info address

push_vlan_tag might change the packet_info address, so
we must refetch the address.
fix typo
Merge branch 'trivial0' of https://github.com/iHiroakiKawai/trema-edge into trivial0
Merge pull request #64 from iHiroakiKawai/trivial0

refetch the packet_info address