[BUGFIX] Invalid definition in ext_tables.sql

Change-Id: I14c10c799bc22381f4f6a1f21cb5045086930a34
Reviewed-on: http://review.typo3.org/32371
Reviewed-by: Xavier Perseguers <xavier@typo3.org>
Tested-by: Xavier Perseguers <xavier@typo3.org>