caddy-frontend: Correctly fix prefer-gzip-encoding-to-backend

Because of misleading tests (Accept-Encoding with gzip was always set by
requests, fixed in "caddy-frontend/test: Workaround requests issue with
Accept-Encoding") the original commit "Fix/caddy frontend prefer gzip type
zope" did not really fixed the issue for type:zope backend.

software/caddy-frontend/buildout.hash.cfg

@@ -58,7 +58,7 @@ md5sum = f20d6c3d2d94fb685f8d26dfca1e822b
 
 [template-default-slave-virtualhost]
 filename = templates/default-virtualhost.conf.in
-md5sum = 3b9d7c04206da76edb40740a51e4063c
+md5sum = 6d6faf2e7839feeabcb3bafc8fd9f4bb
 
 [template-cached-slave-virtualhost]
 filename = templates/cached-virtualhost.conf.in

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

@@ -109,6 +109,11 @@
     if {>Accept-Encoding} match "(^gzip,.*|.*, gzip,.*|.*, gzip$|^gzip$)"
     to /prefer-gzip/VirtualHostBase/{scheme}%2F%2F{hostonly}:{{ slave_parameter.get('virtualhostroot-https-port', '443') | int }}%2F{{ slave_parameter.get('path', '').strip('/') }}%2FVirtualHostRoot/{1}
   }
+  rewrite {
+    regexp (.*)
+    if {>Accept-Encoding} not_match "(^gzip,.*|.*, gzip,.*|.*, gzip$|^gzip$)"
+    to /VirtualHostBase/{scheme}%2F%2F{hostonly}:{{ slave_parameter.get('virtualhostroot-https-port', '443') | int }}%2F{{ slave_parameter.get('path', '').strip('/') }}%2FVirtualHostRoot/{1}
+  }
 {%- else %}
   rewrite {
     regexp (.*)
@@ -253,6 +258,11 @@
     if {>Accept-Encoding} match "(^gzip,.*|.*, gzip,.*|.*, gzip$|^gzip$)"
     to /prefer-gzip/VirtualHostBase/{scheme}%2F%2F{hostonly}:{{ slave_parameter.get('virtualhostroot-http-port', '80') | int }}%2F{{ slave_parameter.get('path', '').strip('/') }}%2FVirtualHostRoot/{1}
   }
+  rewrite {
+    regexp (.*)
+    if {>Accept-Encoding} not_match "(^gzip,.*|.*, gzip,.*|.*, gzip$|^gzip$)"
+    to /VirtualHostBase/{scheme}%2F%2F{hostonly}:{{ slave_parameter.get('virtualhostroot-http-port', '80') | int }}%2F{{ slave_parameter.get('path', '').strip('/') }}%2FVirtualHostRoot/{1}
+  }
 {%- else %}
   rewrite {
     regexp (.*)