Enable no-undef-init eslint rule

.eslintrc

@@ -65,6 +65,7 @@
         "no-template-curly-in-string": "warn",
         "no-throw-literal": "error",
         "no-undef": "error",
+        "no-undef-init": "warn",
         "no-unexpected-multiline": "error",
         "no-unneeded-ternary": "error",
         "no-unmodified-loop-condition": "error",

modules/osm/intersection.js

@@ -380,7 +380,7 @@ export function osmIntersection(graph, startVertexId, maxDistance) {
                     if (currPath.indexOf(way.id) !== -1 && currPath.length >= 3) continue;
 
                     // Check all "current" restrictions (where we've already walked the `FROM`)
-                    var restrict = undefined;
+                    var restrict;
                     for (j = 0; j < currRestrictions.length; j++) {
                         var restriction = currRestrictions[j];
                         var f = restriction.memberByRole('from');

test/spec/actions/upgrade_tags.js

@@ -34,7 +34,7 @@ describe('iD.actionUpgradeTags', function () {
 
     it('upgrades a tag with no replacement tags', function () {
         var oldTags = { highway: 'no' },
-            newTags = undefined,
+            newTags,
             entity = iD.osmEntity({ tags: { highway: 'no', name: 'Foo' }}),
             graph  = iD.actionUpgradeTags(entity.id, oldTags, newTags)(iD.coreGraph([entity]));
         expect(graph.entity(entity.id).tags).to.eql({ name: 'Foo' });