Import : Appears to complete succesfully, but no records imported if DB user has insufficient permissions to create temp tables

Currently the import fails but reports "Completed successfully" when DB user doesn't have "create temp table" permissions. The problem is properly reported in CiviCRM.log:

DB error: insufficient permissions

... although the error should be more specific:

"Database Configuration Error: Insufficient permissions. Import requires that the CiviCRM database user has permission to create temporary tables. Contact your site administrator for assistance."

in order to reduce support problems with this issue, we should check for this condition up front (when user access Import wizard) - and throw a fatal error with above message.