records: fix for document default name generator
records: fix for document default name generator

* Adds catching exceptions around `os.makedirs`.

Signed-off-by: Esteban J. G. Gabancho <03cb568148df368b792a31d9c4d06b12dc802700@gmail.com>
Reviewed-by: Jiri Kuncar <2bdffcb416fed3002465740d19a053a39918cbe5@cern.ch>

tiborsimko/invenio-records,inveniosoftware/invenio-records,inveniosoftware/invenio-records,tiborsimko/invenio-records