deposit: jquery datepicker leftovers
deposit: jquery datepicker leftovers

* Removes jQueryUI css which is no longer needed after integrating
  bootstrap-datetimepicker.

Signed-off-by: Lars Holm Nielsen <7eaffca9f7cd98839b5821d0d23e09ff764b82cd@cern.ch>

inveniosoftware/invenio-deposit,inveniosoftware/invenio-deposit,inveniosoftware/invenio-deposit,inveniosoftware/invenio-deposit