minor fixes for geometry compuation during boundary ranking

Go back to using centroid when determining if one admin level
is within another. There are cases where boundaries are slightly
misaligned due to mapping errors (not using the same ways in the
relations).

Only declare boundaries the same when they have the same wikidata
tag _and_ have exactly the same geometry. This works around tagging
errors with the wikidata tag, which happen because of automated
edits to the wikidata tag.

sql/functions/placex_triggers.sql

@@ -585,16 +585,19 @@ BEGIN
     -- First, check that admin boundaries do not overtake each other rank-wise.
     parent_address_level := 3;
     FOR location IN
-      SELECT rank_address, extratags FROM placex
+      SELECT rank_address,
+             (CASE WHEN extratags ? 'wikidata' and NEW.extratags ? 'wikidata'
+                        and extratags->'wikidata' = NEW.extratags->'wikidata'
+                   THEN ST_Equals(geometry, NEW.geometry)
+                   ELSE false END) as is_same
+      FROM placex
       WHERE osm_type = 'R' and class = 'boundary' and type = 'administrative'
             and admin_level < NEW.admin_level and admin_level > 3
             and rank_address > 0
-            and ST_Covers(geometry, NEW.geometry)
+            and geometry && NEW.centroid and _ST_Covers(geometry, NEW.centroid)
       ORDER BY admin_level desc LIMIT 1
     LOOP
-      IF location.extratags ? 'wikidata' and NEW.extratags ? 'wikidata'
-         and location.extratags->'wikidata' = NEW.extratags->'wikidata'
-      THEN
+      IF location.is_same THEN
         -- Looks like the same boundary is replicated on multiple admin_levels.
         -- Usual tagging in Poland. Remove our boundary from addresses.
         NEW.rank_address := 0;