Problem: data consistency check (maximum record length) for a correct
MyISAM table with CHECKSUM=1 and ROW_FORMAT=DYNAMIC option 
may fail due to wrong inner MyISAM parameter. In result we may 
have the table marked as 'corrupted'. 

Fix: properly set MyISAM maximum record length parameter.


myisam/mi_create.c:
  Fix for bug #37310: 'on update CURRENT_TIMESTAMP' option crashes the table
  
  Use HA_OPTION_PACK_RECORD instead of HA_PACK_RECORD (typo?) 
  calculating packed record length.