fix file descriptor leak of epollfd

sapi/fpm/fpm/events/epoll.c

@@ -46,7 +46,7 @@ static struct fpm_event_module_s epoll_module = {
 
 static struct epoll_event *epollfds = NULL;
 static int nepollfds = 0;
-static int epollfd = 0;
+static int epollfd = -1;
 
 #endif /* HAVE_EPOLL */
 
@@ -103,6 +103,10 @@ static int fpm_event_epoll_clean() /* {{{ */
 		free(epollfds);
 		epollfds = NULL;
 	}
+	if (epollfd != -1) {
+		close(epollfd);
+		epollfd = -1;
+	}
 
 	nepollfds = 0;