REORGANIZE PARTITION

There were several problems which lead to this this,
all related to bad error handling.

1) There was several bugs preventing the ddl-log to be used for
   cleaning up created files on error.

2) The error handling after the copy partition rows did not close
   and unlock the tables, resulting in deletion of partitions
   which were in use, which lead InnoDB to put the partition to
   drop in a background queue.