segment fault when access a cs which is not initialized and also base table can't be find

[amutu]

this bug can be reliable repeated: create table a; insert data to a; create cs for a; load data for a cs; restart PG; drop or rename table a; select * from a_get() cause segment fault and pg crash

I think it may caused by autoload which do not check if the cs base table exists.

[knizhnik]

Check is added.