added packet flag for flow offload for compatibility with ZC
added packet flag for flow offload for compatibility with ZC

ntop/PF_RING,opencTM/PF_RING,opencTM/PF_RING,ntop/PF_RING,ntop/PF_RING,ntop/PF_RING,opencTM/PF_RING,ntop/PF_RING,ntop/PF_RING,opencTM/PF_RING,ntop/PF_RING