Fix Dav discovery on iOS, thanks Brad!

data/conf/nginx/site.conf

@@ -14,6 +14,11 @@ server {
   access_log /var/log/nginx/access.log;
   root /web;
 
+  location = /principals/ {
+    rewrite ^ https://$host/SOGo/dav;
+    allow all;
+  }
+
   location ~ \.php$ {
     try_files $uri =404;
     fastcgi_split_path_info ^(.+\.php)(/.+)$;