Improper error handling in YaraScan module

[awest1339]

• https://github.com/mitre/multiscanner/blob/master/modules/Signature/YaraScan.py#L54

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/lib/python3.6/threading.py", line 916, in _bootstrap_inner
    self.run()
  File "/opt/multiscanner/multiscanner.py", line 101, in run
    self.ret = self.__target(*self.__args, **self.__kwargs)
  File "/opt/multiscanner/multiscanner.py", line 258, in _run_module
    results = mod.scan(filelist, conf=conf)
  File "/opt/multiscanner/modules/Signature/YaraScan.py", line 55, in scan
    bad_file = e.message.split('(')[0]
AttributeError: 'SyntaxError' object has no attribute 'message'