test rpl_err_ignoredtables.


sql/log_event.cc:
  Clearing tables to lock list in the event of errors.
  Adding asserts to catch failing to clear the list of tables to lock.
  Releasing allocated memory if the table will not be replicated.
sql/rpl_rli.h:
  Adding assert to ensure post-condition of clear_tables_to_lock().
  Minor rewrites.