minor style fix

Author: chronolaw

src/ngx_http_lua_socket_tcp.c

@@ -160,8 +160,8 @@ enum {
     SOCKET_CONNECT_TIMEOUT_INDEX = 2,
     SOCKET_SEND_TIMEOUT_INDEX = 4,
     SOCKET_READ_TIMEOUT_INDEX = 5,
-    SOCKET_CLIENT_CERT_INDEX = 6 ,
-    SOCKET_CLIENT_PKEY_INDEX   = 7 ,
+    SOCKET_CLIENT_CERT_INDEX  = 6 ,
+    SOCKET_CLIENT_PKEY_INDEX  = 7 ,
 };