innobase/dict/dict0crea.c:
  dict_truncate_index_tree(): Commit the mtr after deleting the
  index tree. Add diagnostics for error cases. Let the caller update
  SYS_INDEXES.PAGE_NO to the new root page number. Return the new
  root page number, or FIL_NULL on error.
innobase/include/dict0crea.h:
  dict_truncate_index_tree(): Commit the mtr after deleting the
  index tree. Add diagnostics for error cases. Let the caller update
  SYS_INDEXES.PAGE_NO to the new root page number. Return the new
  root page number, or FIL_NULL on error.
innobase/include/page0page.ic:
  page_mem_free(): Disable the memset() call, to make it possible to
  recover some data if someone accidentally deletes a large number
  of records from a table.
innobase/log/log0recv.c:
  Do not disable InnoDB Hot Backup specific code in MySQL builds.
innobase/row/row0mysql.c:
  row_truncate_table_for_mysql(): Remove an infinite loop in case
  a SYS_INDEXES record has been deleted. Avoid deadlocks by committing
  and restarting the mini-transaction.
sql/ha_innodb.cc:
  ha_innobase::delete_all_rows(): set trx->active_trans = 1