Cache: added ngx_quit check to ngx_http_file_cache_expire().
Cache: added ngx_quit check to ngx_http_file_cache_expire().

While managing big caches it is possible that expiring old cache items
in ngx_http_file_cache_expire() will take a while.  Added a check for
ngx_quit / ngx_terminate to make sure cache manager can be terminated
while in ngx_http_file_cache_expire().

firebase/nginx,firebase/nginx,firebase/nginx,hy0kl/nginx,firebase/nginx,hy0kl/nginx,hy0kl/nginx