flow: fix ebpf last metric not updated
flow: fix ebpf last metric not updated

safchain/skydive,skydive-project/skydive,lebauce/skydive,lebauce/skydive,safchain/skydive,skydive-project/skydive,skydive-project/skydive,safchain/skydive,safchain/skydive,lebauce/skydive,lebauce/skydive,lebauce/skydive,skydive-project/skydive,skydive-project/skydive,lebauce/skydive,safchain/skydive,skydive-project/skydive,safchain/skydive,safchain/skydive,safchain/skydive,skydive-project/skydive,lebauce/skydive,lebauce/skydive