win32: silence build warning

glocalfileinfo.c: In function '_g_local_file_info_get':
glocalfileinfo.c:1955:11: warning: passing argument 3 of
'get_thumbnail_attributes' from incompatible pointer type [enabled by
default]
           get_thumbnail_attributes (path, info, &statbuf);
           ^
glocalfileinfo.c:1285:1: note: expected 'const struct GStatBuf *' but
argument is of type 'struct _stati64 *'
 get_thumbnail_attributes (const char     *path,

https://bugzilla.gnome.org/show_bug.cgi?id=711547

gio/thumbnail-verify.c

@@ -224,7 +224,7 @@ out:
 gboolean
 thumbnail_verify (const char     *thumbnail_path,
                   const gchar    *file_uri,
-                  const GStatBuf *file_stat_buf)
+                  const GLocalFileStat *file_stat_buf)
 {
   gboolean thumbnail_is_valid = FALSE;
   ExpectedInfo expected_info;