tools: measure-fuzz: fix exception printing

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/x86_64-linux-gnu/libinput/libinput-measure-fuzz", line 464, in <module>
    main(sys.argv)
  File "/usr/lib/x86_64-linux-gnu/libinput/libinput-measure-fuzz", line 458, in main
    print('Error: {}'.format(e.message))
AttributeError: 'InvalidConfigurationError' object has no attribute 'message'

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net&gt;:>