[BUGFIX] no hover effect for db_list

If alternateBgColors in pageTSconfig is set
you have more contrast in db_list, but there
is no hover effect for the darker rows

Resolves: #23536
Releases: 6.2, 6.1, 6.0
Change-Id: If17aa33e414edda0ea1ce8bf3b5ca1576a759c11
Reviewed-on: https://review.typo3.org/25409
Reviewed-by: Philipp Gampe
Tested-by: Philipp Gampe
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters