BUG/MINOR: kqueue/threads: Don't forget to close kqueue_fd[tid] on each thread

in deinit_kqueue_per_thread, kqueue_fd[tid] must be closed, except for the main
thread (the first one, tid==0).

This patch must be backported in 1.8 with commit 7a2364d4.

src/ev_kqueue.c

@@ -184,6 +184,9 @@ static int init_kqueue_per_thread()
 
 static void deinit_kqueue_per_thread()
 {
+	if (tid)
+		close(kqueue_fd[tid]);
+
 	free(kev);
 	kev = NULL;
 }