Fix deployment using Deploy to Heroku button

Remove reference to Project.url field which was removed in #2862.

pontoon/base/management/commands/heroku_deploy_setup.py

@@ -1,11 +1,11 @@
 import os
 
-from urllib.parse import urlparse, urljoin
+from urllib.parse import urlparse
 
 from django.core.management.base import BaseCommand
 from django.contrib.sites.models import Site
 
-from pontoon.base.models import Project, User
+from pontoon.base.models import User
 
 
 class Command(BaseCommand):
@@ -19,7 +19,3 @@ def handle(self, *args, **options):
 
         User.objects.create_superuser(admin_email, admin_email, admin_password)
         Site.objects.filter(pk=1).update(name=app_host, domain=app_host)
-
-        Project.objects.filter(slug="pontoon-intro").update(
-            url=urljoin(site_url, "intro/")
-        )