m1n1.adt: Add missing 'sys' import

Used for sys.stderr later on.

Signed-off-by: Martin Povišer <[email protected]>

Author: povik

proxyclient/m1n1/adt.py

@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: MIT
 import itertools, fnmatch, sys
 from construct import *
+import sys
 
 from .utils import AddrLookup, FourCC, SafeGreedyRange