fix the other call to read_set_seek_callback

Author: Changaco

libarchive/read.py

@@ -65,9 +65,10 @@ def custom_reader(
     open_cb = OPEN_CALLBACK(open_func) if open_func else NO_OPEN_CB
     read_cb = READ_CALLBACK(read_func)
     close_cb = CLOSE_CALLBACK(close_func) if close_func else NO_CLOSE_CB
+    seek_cb = SEEK_CALLBACK(seek_func)
     with new_archive_read(format_name, filter_name, passphrase) as archive_p:
         if seek_func:
-            ffi.read_set_seek_callback(archive_p, SEEK_CALLBACK(seek_func))
+            ffi.read_set_seek_callback(archive_p, seek_cb)
         ffi.read_open(archive_p, None, open_cb, read_cb, close_cb)
         yield archive_read_class(archive_p)