Make create/drop catalog atomic

Add create catalog and drop catalog to ddl_log (to make them atomic)

• If create catalog fails in the middle, we should delete the catalog files (my.cnf, catalog.opt) and drop the directory.

• Not sure what to do if 'drop catalog' had started as the user may have killed the server to not
  loose all data. One option is to finish the drop only if the catalog directory does not hold any
  other data than the catalog configuration files.