fix fd leak on BPF open failure. from juan@foxpaw.com
fix fd leak on BPF open failure. from juan@foxpaw.com

jncornett/libdnet,jncornett/libdnet,kbandla/libdnet,jncornett/libdnet,kbandla/libdnet,wtfbbqhax/libdnet,kbandla/libdnet,wtfbbqhax/libdnet,wtfbbqhax/libdnet