4 bytes, using my_checksum() (the old checksum was one byte and just
a sum of the bytes - that was before I saw we have my_checksum :)


storage/maria/ma_control_file.c:
  stronger checksum (4 bytes instead of 1, and using CRC instead of
  simple byte sum).
storage/maria/unittest/ma_control_file-t.c:
  Checksum is now 4 bytes (total length of control file is now 23),
  so LSN and LAST_LOGNO move.