Setting $args now invalidates unparsed uri.

Prodded by Yichun Zhang.
diff --git a/src/http/ngx_http_variables.c b/src/http/ngx_http_variables.c
index 5bd6b96..1b61c39 100644
--- a/src/http/ngx_http_variables.c
+++ b/src/http/ngx_http_variables.c
@@ -13,8 +13,10 @@
 
 static ngx_int_t ngx_http_variable_request(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data);
+#if 0
 static void ngx_http_variable_request_set(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data);
+#endif
 static ngx_int_t ngx_http_variable_request_get_size(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data);
 static void ngx_http_variable_request_set_size(ngx_http_request_t *r,
@@ -64,6 +66,8 @@
     ngx_http_variable_value_t *v, uintptr_t data);
 static ngx_int_t ngx_http_variable_https(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data);
+static void ngx_http_variable_set_args(ngx_http_request_t *r,
+    ngx_http_variable_value_t *v, uintptr_t data);
 static ngx_int_t ngx_http_variable_is_args(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data);
 static ngx_int_t ngx_http_variable_document_root(ngx_http_request_t *r,
@@ -223,7 +227,7 @@
       NGX_HTTP_VAR_NOCACHEABLE, 0 },
 
     { ngx_string("args"),
-      ngx_http_variable_request_set,
+      ngx_http_variable_set_args,
       ngx_http_variable_request,
       offsetof(ngx_http_request_t, args),
       NGX_HTTP_VAR_CHANGEABLE|NGX_HTTP_VAR_NOCACHEABLE, 0 },
@@ -662,6 +666,8 @@
 }
 
 
+#if 0
+
 static void
 ngx_http_variable_request_set(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data)
@@ -674,6 +680,8 @@
     s->data = v->data;
 }
 
+#endif
+
 
 static ngx_int_t
 ngx_http_variable_request_get_size(ngx_http_request_t *r,
@@ -1371,6 +1379,16 @@
 }
 
 
+static void
+ngx_http_variable_set_args(ngx_http_request_t *r,
+    ngx_http_variable_value_t *v, uintptr_t data)
+{
+    r->args.len = v->len;
+    r->args.data = v->data;
+    r->valid_unparsed_uri = 0;
+}
+
+
 static ngx_int_t
 ngx_http_variable_is_args(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data)