WebSearch: fix nearest terms offer for date search
WebSearch: fix nearest terms offer for date search

* Fix nearest terms offer for datecreated/datemodified searches.
  (closes #310)

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