Upstream: simplified Content-Encoding handling. Since introduction of offset handling in ngx_http_upstream_copy_header_line() in revision 573:58475592100c, the ngx_http_upstream_copy_content_encoding() function is no longer needed, as its behaviour is exactly equivalent to ngx_http_upstream_copy_header_line() with appropriate offset. As such, the ngx_http_upstream_copy_content_encoding() function was removed. Further, the u->headers_in.content_encoding field is not used anywhere, so it was removed as well. Further, Content-Encoding handling no longer depends on NGX_HTTP_GZIP, as it can be used even without any gzip handling compiled in (for example, in the charset filter).