handle a sendfile() = 0 is connection closed by remote side

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-merge-1.4.x@930 152afb58-edef-0310-8abb-c4023f1b3aa9

src/network_linux_sendfile.c

@@ -173,6 +173,11 @@ int network_write_chunkqueue_linuxsendfile(server *srv, connection *con, int fd,
 					return -1;
 				}
 			}
+
+			if (r == 0) {
+				/* we got a event to write put we couldn't. remote side closed ? */
+				return -2;
+			}
 			
 			c->offset += r;
 			cq->bytes_out += r;