fixup admin import style and add two new ones

Remove unnamed landuses and postcode points from
importing. The latter will cause all objects with
address tags to be imported after all. Not expected
in the admin import style.

settings/import-admin.style

@@ -26,7 +26,7 @@
     "keys" : ["landuse"],
     "values" : {
         "cemetry" : "skip",
-        "" : "fallback"
+        "" : "fallback,with-name"
     }
 },
 {
@@ -41,13 +41,6 @@
         "" : "main"
     }
 },
-{
-    "keys" : ["postal_code", "postcode", "addr:postcode",
-              "tiger:zip_left", "tiger:zip_right"],
-    "values" : {
-        "" : "postcode"
-    }
-},
 {
     "keys" : ["country_code", "ISO3166-1", "is_in:country_code", "is_in_country",
               "addr:country", "addr:country", "addr:country_code"],