Add check to make sure that Drupal and CiviCRM tables are using the same db engine

Mixing MyISAM and Innodb tables can cause performance issues.

http://stackoverflow.com/questions/5475283/joining-innodb-tables-with-my...

It is possible to create a CiviCRM Starter Kit on Pantheon that uses Innodb for Drupal and MyISAM for CiviCRM. Need a simple status check to make sure that isn't the case and show a warning if it is.