fix: return proper error message when no certificate is presented

Author: fstagni

src/DIRAC/Core/Tornado/Server/private/BaseRequestHandler.py

@@ -739,6 +739,8 @@ def _authzSSL(self):
         elif balancer:
             if self.request.headers.get("X-Ssl_client_verify") == "SUCCESS" and self.request.headers.get("X-SSL-CERT"):
                 chainAsText = unquote(self.request.headers.get("X-SSL-CERT"))
+	    else:
+		return S_ERROR(DErrno.ECERTFIND, "Valid certificate not found.")
         else:
             return S_ERROR(DErrno.ECERTFIND, "Valid certificate not found.")