Proxy: $proxy_internal_body_length fixed.
Proxy: $proxy_internal_body_length fixed.

The $proxy_internal_body_length value might change during request lifetime,
notably if proxy_set_body used, and use of a cached value might result in
incorrect upstream requests.

Patch by Lanshun Zhou.

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