search: fix for return key handling in search form
search: fix for return key handling in search form

* Fixes an issue where pressing the return key in the simple search
  dropdown caused the form to be submitted with no data. (closes #2253)
  (PR #2282)

Reviewed-by: Jiri Kuncar <2bdffcb416fed3002465740d19a053a39918cbe5@cern.ch>
Signed-off-by: Joe MacMahon <4ca268e9bec04d8527d4a2f68a8f8b0a83947984@cern.ch>

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