XMLDB check_indexes options runs for too long and PHP stops the script.

When we try to check the database indexes from Admin->Misc->XMLDB editor->Check Indexes, after we confirm the run, we get a blank page after some time.

It seems index checking is taking longer than the configured max_execution_time and PHP stops executing the page. We should raise the execution time before calling '$xmldb_action->invoke();' to cater for this. I've tried with 'set_time_limit(0)' and it works ok, but I don't know the code so maybe this is a little bit too much and we could use a lower limit.

Saludos. Iñaki.