- Changed COLUMN_FORMAT default to be DYNAMIC when defining new tables.
- If COLUMN_FORMAT is omitted or defined as DEFAULT the column will
  now use variable-width storage unless it is overridden by a ROW_FORMAT
  specifier or if the column is defined with COLUMN_STORAGE DISK.
- Old tables (restored from backup) still keep the old FIXED COLUMN_FORMAT
  as default.
- Added warnings if user does an ALTER TABLE with implicit copy that will
  change the COLUMN_FORMAT (if table was created in older version and with
  no specific COLUMN_FORMAT defined).
- Added a new configuration option --ndb-default-column-format = [FIXED|DYNAMIC]
  to allow user to overide the new default value.