DPDK: update to 18.11.5.

Update release note or 1.13.

travis-ci:fix the permission of dpdk's shell files.

Fix F-Stack#107: some invalid usages of kqueue in `ff_epoll`.

1.Both EVFILT_READ and EVFILT_WRITE are values but not flags. It needs to check whether it is equal but not to do logic and.

2.If the read direction of the socket has shutdown, then the filter also sets EV_EOF in `flags`, and returns the socket error (if any) in `fflags`.