Slight improvement of generic.lua config

We "split" up the relations based on the type onto different tables here
and there is no case where the type tag will be useful in the database
and everything without type is dropped anyway.

Fixes #1441

Author: joto

flex-config/generic.lua

@@ -248,12 +248,12 @@ function osm2pgsql.process_way(object)
 end
 
 function osm2pgsql.process_relation(object)
+    local type = object:grab_tag('type')
+
     if clean_tags(object.tags) then
         return
     end
 
-    local type = object.tags.type
-
     if type == 'route' then
         tables.routes:add_row({
             tags = object.tags,
@@ -270,7 +270,7 @@ function osm2pgsql.process_relation(object)
         return
     end
 
-    if object.tags.type == 'multipolygon' then
+    if type == 'multipolygon' then
         tables.polygons:add_row({
             tags = object.tags,
             geom = { create = 'area' }