avoid ProcessLookupError for already-terminated processes

Author: dlenski

tetherback/tetherback.py

@@ -296,8 +296,8 @@ def uevent_dict(path):
         with open(fn+'.md5', 'w') as md5out:
             print('%s *%s' % (localmd5, fn), file=md5out)
 
+    child.wait()
     if args.transport==adbxp.tcp:
         s.close()
         if not really_unforward(port):
             raise RuntimeError('could not remove ADB-forward for TCP port %d' % port)
-    child.terminate()