Use getattr for checking subdomain and cname on request

Author: humitos

readthedocs/core/views/__init__.py

@@ -133,7 +133,7 @@ def server_error_404(request, exception=None, template_name='404.html'):  # pyli
             return response
 
     # Try to serve custom 404 pages if it's a subdomain/cname
-    if request.subdomain or request.cname:
+    if getattr(request, 'subdomain', False) or getattr(request, 'cname', False):
         return server_error_404_subdomain(request, template_name)
 
     # Return the default 404 page generated by Read the Docs

readthedocs/doc_builder/python_environments.py

@@ -443,7 +443,7 @@ def install_core_requirements(self):
         cmd.extend(requirements)
         self.build_env.run(
             *cmd,
-            cwd=self.checkout_path  # noqa - no comma here in py27 :/
+            cwd=self.checkout_path,
         )
 
         pip_cmd = [