caddy-frontend: Fix backend Via header for https backend

Rarely used https backend was missing the backend Via additions, thus it was
not transmitted there.

software/caddy-frontend/buildout.hash.cfg

@@ -50,7 +50,7 @@ md5sum = 57c86795293b11300a036f5f8cf2c868
 
 [template-backend-haproxy-configuration]
 _update_hash_filename_ = templates/backend-haproxy.cfg.in
-md5sum = 6d4ad68ac44ccc72fe9148bd8e05a6f0
+md5sum = 81c73a4995409acb548621e5fb11d481
 
 [template-empty]
 _update_hash_filename_ = templates/empty.in

software/caddy-frontend/templates/backend-haproxy.cfg.in

@@ -69,6 +69,8 @@ frontend http-backend
 
 frontend https-backend
   bind {{ configuration['local-ipv4'] }}:{{ configuration['https-port'] }}
+  http-request add-header Via "%HV rapid-cdn-backend-{{ configuration['node-id'] }}-{{ configuration['version-hash'] }}"
+  http-response add-header Via "%HV rapid-cdn-backend-{{ configuration['node-id'] }}-{{ configuration['version-hash']}}"
 {%- for slave_instance in backend_slave_list -%}
 {{ frontend_entry(slave_instance, 'https', False) }}
 {%- endfor %}

software/caddy-frontend/test/test.py

@@ -4532,6 +4532,9 @@ class TestSlave(SlaveHttpFrontendTestCase, TestDataMixin):
       result.headers['Strict-Transport-Security'])
 
     self.assertEqualResultJson(result, 'Path', '/https/test-path/deeper')
+    self.assertBackendHeaders(
+      result.json()['Incoming Headers'],
+      parameter_dict['domain'])
 
     result_http = fakeHTTPResult(
       parameter_dict['domain'],