CRM-14811 - Add setting "enable_innodb_fts". Changes trigger InnoDBIndexer->fixSchemaDifferences.
CRM-14811 - FullText - Use InnoDB FTS when available.
CRM-14811 - "Adminster => System => Misc" - Add option to enable InnoDB FTS
CRM-14811 - Check "enable_innodb_fts" during upgrades