refs #6090 use an index scan of the primary rather than an full table scan + sort.  get 2458.test to work on maria 5.5.28a

git-svn-id: file:///svn/mysql.com/mariadb-5.5.30@54906 c7de825b-a66e-492c-adef-691d508d4ae1
refs #6090 expand format size for row_format

git-svn-id: file:///svn/mysql.com/mariadb-5.5.30@54907 c7de825b-a66e-492c-adef-691d508d4ae1