When boundaries are shared with roads, consider them as roads.

(closes #4973)

This is same as existing logic in the feature matching code
for the "rail" and "past_future" rules.

modules/renderer/features.js

@@ -138,7 +138,13 @@ export function rendererFeatures(context) {
     });
 
     defineFeature('boundaries', function isBoundary(entity) {
-        return !!entity.tags.boundary;
+        return (
+            !!entity.tags.boundary
+        ) && !(
+            traffic_roads[entity.tags.highway] ||
+            service_roads[entity.tags.highway] ||
+            paths[entity.tags.highway]
+        );
     });
 
     defineFeature('water', function isWater(entity) {
@@ -483,7 +489,7 @@ export function rendererFeatures(context) {
             var storageDisabled = storage.replace(/;/g, ',').split(',');
             storageDisabled.forEach(features.disable);
         }
-        
+
         var q = utilStringQs(window.location.hash.substring(1));
         if (q.disable_features) {
             var hashDisabled = q.disable_features.replace(/;/g, ',').split(',');

test/spec/renderer/features.js

@@ -166,6 +166,7 @@ describe('iD.Features', function() {
 
             // Boundaries
             iD.Way({id: 'boundary', tags: {boundary: 'administrative'}, version: 1}),
+            iD.Way({id: 'boundary_road', tags: {boundary: 'administrative', highway: 'primary'}, version: 1}),
 
             // Water
             iD.Way({id: 'water', tags: {area: 'yes', natural: 'water'}, version: 1}),
@@ -251,7 +252,7 @@ describe('iD.Features', function() {
                 'motorway', 'motorway_link', 'trunk', 'trunk_link',
                 'primary', 'primary_link', 'secondary', 'secondary_link',
                 'tertiary', 'tertiary_link', 'residential', 'living_street',
-                'unclassified', 'inner3'
+                'unclassified', 'boundary_road', 'inner3'
             ]);
 
             dontMatch([
@@ -340,6 +341,7 @@ describe('iD.Features', function() {
             ]);
 
             dontMatch([
+                'boundary_road',   // because boundary also used as highway - #4973
                 'point_bar', 'motorway', 'service', 'path', 'building_yes',
                 'forest', 'water', 'railway', 'power_line',
                 'motorway_construction', 'fence'