No spider variables available is Spider is loaded upon server startup

Run in MTR with --mysqld=--plugin-load-add=ha_spider (or start the server with the option) and run in the client.

show engines;

show variables like 'spider%';

Engine	Support	Comment	Transactions	XA	Savepoints

SPIDER	YES	Spider storage engine	YES	YES	NO

...

show variables like 'spider%';

Variable_name	Value

No variables. If however spider is installed at runtime via INSTALL SONAME, then variables are loaded.

Run without plugin-load-add=ha_spider:

Variable_name	Value

spider_auto_increment_mode	0

spider_bgs_first_read	2

<... many more...>

spider_wait_timeout	604800

spider_xa_register_mode	1

This is a regression from the previous release set (unless on some reason it is intentional).