Moved proxy_cache_path in Nginx global conf (refs #18553).

6.Nginx/vhost_mediaserver-msuser.conf

-# for a 20 Mbits/s stream, we want to keep maybe 10s of video, 40 streams means 1 GB
-proxy_cache_path /tmp levels=1:2 keys_zone=livecache:10m max_size=2g inactive=30s;
-
 geo $msuser_whitelist {
 	default 0;
 	127.0.0.1 1;