fix set-vlan byteorder

bytes in a frame are stored in network byte order.
vlan priority bit shifts was wrong.
fix set-vlan byteorder

bytes in a frame are stored in network byte order.
vlan priority bit shifts was wrong.
Merge branches 'fix_set_vlan' and 'fix_set_vlan' of https://github.com/iHiroakiKawai/trema-edge into fix_set_vlan
Merge pull request #68 from iHiroakiKawai/fix_set_vlan

fix set-vlan byteorder