[BUGFIX] Fix misleading SQL error message in TCEforms

When an SQL error occurs, TCEforms shows the error message
 "This may indicate a table defined in tables.php is not
 existing in the database!"

The error can be caused by any schema mismatch, not only
missing table, so this is misleading.

The error message is now localizable and gives a hint to
run the database compare in the install tool.

Change-Id: I31bea64cf656c951bc63a89eff47fbeb893ae73f
Resolves: #16306
Releases: 4.6, 4.5
Reviewed-on: http://review.typo3.org/4764
Reviewed-by: Steffen Gebert
Tested-by: Steffen Gebert
Reviewed-by: Xavier Perseguers
Tested-by: Xavier Perseguers