dbdump: partial dumps
dbdump: partial dumps

* Creates DB dumps into files with extension .part
  and only at the very end, when the dump is confirmed
  to have actually succeeded, does rename the file
  by removing the .part extension.
  In this way it is clear whether a dump actually
  failed in the middle or not.

tiborsimko/invenio,tiborsimko/invenio,inveniosoftware/invenio,inveniosoftware/invenio