epoll: close fd on alloc fail at initialization

If the memory allocations fail then we free any other allocated
structures but don't close the file descriptor resulting in an leak of
fd's.

epoll.c

@@ -120,15 +120,18 @@ epoll_init(struct event_base *base)
 
 	evutil_make_socket_closeonexec(epfd);
 
-	if (!(epollop = mm_calloc(1, sizeof(struct epollop))))
+	if (!(epollop = mm_calloc(1, sizeof(struct epollop)))) {
+		close(epfd);
 		return (NULL);
+	}
 
 	epollop->epfd = epfd;
 
 	/* Initialize fields */
 	epollop->events = mm_calloc(INITIAL_NEVENT, sizeof(struct epoll_event));
 	if (epollop->events == NULL) {
 		mm_free(epollop);
+		close(epfd);
 		return (NULL);
 	}
 	epollop->nevents = INITIAL_NEVENT;