more verbose error handling

buttond.py

@@ -69,8 +69,8 @@ for b in config.get('button', 'names').split(','):
 # clear temp variables off the stack
 try:
     del pin, closed, opened
-except (NameError):
-    pass
+except NameError as e:
+    print('failed to release memory', e)
 
 
 # when run directly, sleep until button signal or KeyboardInterrupt