heap/hp_delete.c:
  added code for right calculation 
  of Index_length in HEAP tables with BTREE indexes
heap/hp_write.c:
  added code for right calculation 
  of Index_length in HEAP tables with BTREE indexes
mysql-test/r/show_check.result:
  added test for BUG #2719 "Heap tables status shows wrong or missing data"
mysql-test/t/show_check.test:
  added test for BUG #2719 "Heap tables status shows wrong or missing data"