Proxy: whitespaces after chunk size allowed.

Whitespaces after chunk size seems to be be allowed by the "implied *LWS" rule
and emitted by some servers.

src/http/modules/ngx_http_proxy_module.c

diff --git a/src/http/modules/ngx_http_proxy_module.c b/src/http/modules/ngx_http_proxy_module.c
index 88ee424..78e2765 100644
--- a/src/http/modules/ngx_http_proxy_module.c
+++ b/src/http/modules/ngx_http_proxy_module.c
@@ -1647,6 +1647,8 @@
                     state = sw_trailer;
                     break;
                 case ';':
+                case ' ':
+                case '\t':
                     state = sw_last_chunk_extension;
                     break;
                 default:
@@ -1664,6 +1666,8 @@
                 state = sw_chunk_data;
                 break;
             case ';':
+            case ' ':
+            case '\t':
                 state = sw_chunk_extension;
                 break;
             default: