innobase/include/data0type.ic:
  dtype_get_fixed_size(), dtype_get_min_size(): Do not check
  prtype, mbminlen and mbmaxlen for types other than DATA_MYSQL,
  as that is the only type that can hold fixed-length strings of
  variable-length objects (UTF-8 encoded characters).
innobase/row/row0sel.c:
  row_sel_field_store_in_mysql_format(): Document which fields of
  templ will be used.  Add 0x20 padding only to DATA_MYSQL fields.
  Change related debug assertions to real assertions for now, until
  5.0 becomes generally available.  Check with assertion that all
  data types handled in the catch-all branch are appropriate.