win32: silence build warning

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