wsgi: Use a more precise Content-Type when providing the CA certificate.

caucase/wsgi.py

@@ -314,7 +314,7 @@ class Application(object):
       raise NotFound
     if crt_id == 'ca.crt.pem':
       data = context.getCACertificate()
-      content_type = 'application/pkix-cert'
+      content_type = 'application/x-x509-ca-cert'
     elif crt_id == 'ca.crt.json':
       data = json.dumps(context.getValidCACertificateChain())
       content_type = 'application/json'