fix(nginx): set worker_processes to auto

See http://nginx.org/en/docs/ngx_core_module.html#worker_processes

Author: Matthew Fisher

rootfs/etc/nginx/nginx.conf

@@ -1,5 +1,5 @@
 user nginx;
-worker_processes 1;
+worker_processes auto;
 
 error_log   /var/log/nginx/error.log    warn;
 pid         /var/run/nginx.pid;