Upstream: simplified Accept-Ranges handling.

The u->headers_in.accept_ranges field is not used anywhere and hence removed.

src/http/ngx_http_upstream.c

diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
index 4bf207b..b480f55 100644
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -259,8 +259,7 @@
                  offsetof(ngx_http_headers_out_t, expires), 1 },
 
     { ngx_string("Accept-Ranges"),
-                 ngx_http_upstream_process_header_line,
-                 offsetof(ngx_http_upstream_headers_in_t, accept_ranges),
+                 ngx_http_upstream_ignore_header_line, 0,
                  ngx_http_upstream_copy_allow_ranges,
                  offsetof(ngx_http_headers_out_t, accept_ranges), 1 },
 

src/http/ngx_http_upstream.h

diff --git a/src/http/ngx_http_upstream.h b/src/http/ngx_http_upstream.h
index c402d83..1ccfb8f 100644
--- a/src/http/ngx_http_upstream.h
+++ b/src/http/ngx_http_upstream.h
@@ -280,7 +280,6 @@
 
     ngx_table_elt_t                 *last_modified;
     ngx_table_elt_t                 *location;
-    ngx_table_elt_t                 *accept_ranges;
     ngx_table_elt_t                 *www_authenticate;
     ngx_table_elt_t                 *transfer_encoding;
     ngx_table_elt_t                 *vary;