Use PG_FINALLY to simplify code

[Hou, Zhijie]

Hi

In (/src/pl/plpgsql/src/pl_exec.c), I found some code like the following:

        PG_CATCH();
        {
                if (expr->plan && !expr->plan->saved)
                        expr->plan = NULL;
                PG_RE_THROW();
        }
        PG_END_TRY();

        if (expr->plan && !expr->plan->saved)
                expr->plan = NULL;

Since PG_FINALLY can be used now, I think we can use PG_FINALLY to simplify 
code here.

Best regards,
houzj

0001-adjust-code-to-use-PG_FINALLY.patch
Description: 0001-adjust-code-to-use-PG_FINALLY.patch