MB-6942: Don't return "node": "local"

I don't have an idea why I originally returned "node": "local"
for every row. It works also without.

Change-Id: If782c19ff6fe1cf40f184f179a3aef876008cc66
Reviewed-on: http://review.couchbase.org/21717
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Filipe David Borba Manana <fdmanana@gmail.com>

src/geocouch/couch_spatial_merger.erl

@@ -103,7 +103,6 @@ spatial_row_obj({{Bbox, DocId}, {{Type, Coords}, Value}}) ->
       ",\"bbox\":", (?JSON_ENCODE(tuple_to_list(Bbox)))/binary,
       ",\"geometry\":",
       (?JSON_ENCODE({[{type, Type}, {coordinates, Coords}]}))/binary,
-      ",\"node\":\"", (?LOCAL)/binary, "\"",
       ",\"value\":", (?JSON_ENCODE(Value))/binary, "}">>.
 
 spatial_less_fun(A, B) ->