fix(auth): pass project id to gax clients (#447)

Author: callmehiphop

handwritten/pubsub/src/index.ts

@@ -806,6 +806,8 @@ export class PubSub {
           return;
         }
         this.projectId = projectId!;
+        this.options.projectId = projectId!;
+
         this.getClient_(config, callback);
       });
       return;

handwritten/pubsub/test/index.ts

@@ -1084,6 +1084,7 @@ describe('PubSub', () => {
         pubsub.getClient_(CONFIG, err => {
           assert.ifError(err);
           assert.strictEqual(pubsub.projectId, PROJECT_ID);
+          assert.strictEqual(pubsub.options.projectId, PROJECT_ID);
           done();
         });
       });