top-level statement) and fixes for the bugs it finds.
Fix for non-serious Valgrind warning.


sql/sql_insert.cc:
  When CREATE TABLE IF NOT EXISTS finds the table already exists,
  'table' is the existing table. So if that table is temporary we don't
  re-enable transactions which is a bug.
sql/sql_parse.cc:
  verify that at the end of each top-statement transactions have
  been re-enabled. Does not apply to substatements (consider
  CREATE TABLE t1 SELECT stored_func() : the substatements inside
  stored_func() run with transaction disabled).
  I am not putting the assertion into ha_external_lock(F_UNLCK) because
  performance schema tables get closed in the middle of a statement
  sometimes while transaction is disabled.
sql/sql_table.cc:
  copy_data_between_tables() forgot to clean-up several things in error
  conditions (ha_enable_transaction(), free-ing 'copy', etc) as found
  by the assertion added to sql_parse.cc.
storage/maria/ha_maria.cc:
  Comment
storage/maria/ma_blockrec.c:
  fix for Valgrind warning: a temporary table was created, a blob
  page of its was flushed to disk and had random bytes in the checksum
  area ("write of uninitialized bytes in pwrite")
storage/maria/ma_pagecrc.c:
  typo