caddy-frontend: Assert and fix HTTP redirect codes

Just asserting Location header is not enough, as http status code value is
important for the implementation, so assert for its value.

Also fix https-only redirect status code value, which supposed to be FOUND,
not default MOVED_PERMANENTLY.

/reviewed-on nexedi/slapos!485

software/caddy-frontend/buildout.hash.cfg

@@ -58,7 +58,7 @@ md5sum = f20d6c3d2d94fb685f8d26dfca1e822b
 
 [template-default-slave-virtualhost]
 filename = templates/default-virtualhost.conf.in
-md5sum = 55d0ca695318d7d6111742f4b37fe1b8
+md5sum = 065bdb954a4c05c538d8264b6ad43fba
 
 [template-cached-slave-virtualhost]
 filename = templates/cached-virtualhost.conf.in

software/caddy-frontend/templates/default-virtualhost.conf.in

@@ -198,7 +198,9 @@
 
 {%- if https_only %}
   # Enforced redirection to SSL-enabled host
-  redir / https://{host}{rewrite_uri}
+  redir 302 {
+    / https://{host}{rewrite_uri}
+  }
 {%- elif slave_type ==  'redirect' and slave_parameter.get('url', '') %} {#- if https_only #}
   # Redirect configuration
   redir 302 {

software/caddy-frontend/test/test.py

@@ -1290,6 +1290,11 @@ http://apachecustomhttpsaccepted.example.com:%%(http_port)s {
       self.certificate_pem,
       der2pem(result.peercert))
 
+    self.assertEqual(
+      httplib.MOVED_PERMANENTLY,
+      result.status_code
+    )
+
     self.assertEqual(
       'https://typezopedefaultpath.example.com:%s/default-path' % (
         HTTPS_PORT,),
@@ -1544,6 +1549,11 @@ http://apachecustomhttpsaccepted.example.com:%%(http_port)s {
       parameter_dict['domain'], parameter_dict['public-ipv4'],
       'test-path/deep/.././deeper')
 
+    self.assertEqual(
+      httplib.FOUND,
+      result_http.status_code
+    )
+
     self.assertEqual(
       'https://httpsonly.example.com/test-path/deeper',
       result_http.headers['Location']
@@ -1936,6 +1946,11 @@ http://apachecustomhttpsaccepted.example.com:%%(http_port)s {
       self.certificate_pem,
       der2pem(result.peercert))
 
+    self.assertEqual(
+      httplib.FOUND,
+      result.status_code
+    )
+
     self.assertEqual(
       '%s/test-path/deeper' % (self.backend_url,),
       result.headers['Location']
@@ -3974,6 +3989,11 @@ https://www.google.com {}""",
       self.certificate_pem,
       der2pem(result.peercert))
 
+    self.assertEqual(
+      httplib.MOVED_PERMANENTLY,
+      result.status_code
+    )
+
     self.assertEqual(
       'https://defaultpathunsafe.example.com:%s/%%24%%7Bsection%%3Aoption%%7D'
       '%%0An%%22%%0Aewline%%0A%%7D%%0A%%7Dproxy%%0A/slashed' % (HTTPS_PORT,),