"Table upgrade required..."

The row format is only different for the case where we have a very old MyISAM table with varchar fields, null fields and created with CHECKSUM=1
The table is usable, except that CHECKSUM TABLE will give a wrong result and CHECK TABLE will warn about this.

I added a test for this to warn when a table needs to be upgraded, but forgot to add a test that this was only relevant for tables with CHECKSUM=1
This is now fixed.



storage/myisam/ha_myisam.cc:
  Fixed wrong test.