pgsql: Fix thinkos from 4f4061b for libpq integer parsing

Fix thinkos from 4f4061b for libpq integer parsing A check was redundant. While on it, add an assertion to make sure that the parsing routine is never called with a NULL input. All the code paths currently calling the parsing routine are careful with NULL inputs already, but future callers may f

pgsql: Fix thinkos from 4f4061b for libpq integer parsing

Fix thinkos from 4f4061b for libpq integer parsing A check was redundant. While on it, add an assertion to make sure that the parsing routine is never called with a NULL input. All the code paths currently calling the parsing routine are careful with NULL inputs already, but future callers may f