optimize: fixed the pre-allocated number of keys in the 'ngx.socket.tcp' table.

Author: thibaultcha

src/ngx_http_lua_socket_tcp.c

@@ -304,7 +304,7 @@ ngx_http_lua_inject_socket_tcp_api(ngx_log_t *log, lua_State *L)
     /* {{{tcp object metatable */
     lua_pushlightuserdata(L, ngx_http_lua_lightudata_mask(
                           tcp_socket_metatable_key));
-    lua_createtable(L, 0 /* narr */, 12 /* nrec */);
+    lua_createtable(L, 0 /* narr */, 13 /* nrec */);
 
     lua_pushcfunction(L, ngx_http_lua_socket_tcp_connect);
     lua_setfield(L, -2, "connect");