Make land_use into a multivalued field
Make land_use into a multivalued field

It is multivalued, and not configuring it as such breaks running
migrations (and will stop new documents with this field in being
indexed).

(This was never a problem in production because we caught it in
preview.)

theodi/rummager,theodi/rummager,alphagov/rummager,alphagov/rummager