Fatal when creating InnoDB fts indexes

A fatal error happens in the CRM-Core_InnoDBIndexer class when the CiviCRM database user is not super-privileged (ie. just a regular user with all privileges on the database itself).

debug_info:
SELECT i.name as index_name
FROM information_schema.innodb_sys_tables t
JOIN information_schema.innodb_sys_indexes i USING (table_id)
WHERE t.name = concat(database(),'/civicrm_address')
AND i.name like 'civicrm_fts_%'
[nativecode=1227 ** Access denied; you need (at least one of) the PROCESS privilege(s) for this operation]

I do not know if this is really critical as I have never seen the message on screen, so maybe it is triggered during a cronjob and never shown to a real user.

But still, we should at minimum trap this error if not redesign the mechanism of getting FTS indexes another way (maybe a SHOW CREATE or other unprivileged statement).

Assigning to Tim since he is the creator of this file.