(2.6) hsqldb-plugin: fix transposed varchar settings

The longer varchar (8000) should appear on errormessage but was erroneously given to a different field in a few of the tables.

Target: 2.6
Require-notes: no
Require-book: no
Acked-by: Gerd
Acked-by: Paul
Committed: c8c4807e2dc2475a47fff94a87eba08bc9ba0651