BackslashPlugin.error_added fails on SyntaxError

[ayalash]

Sentry link: http://sentry.infinidat.com/sentry/slash_infinidat-backslash-plug/issues/5114/

SyntaxError: EOL while scanning string literal (<unknown>, line 1)
  File "backslash/contrib/slash_plugin.py", line 49, in new_func
    return func(self, *args, **kwargs)
  File "backslash/contrib/slash_plugin.py", line 373, in error_added
    'traceback': distill_slash_traceback(error), 'exception_attrs': getattr(error, 'exception_attributes', NOTHING)}
  File "backslash/contrib/utils.py", line 30, in distill_slash_traceback
    commands = ast.literal_eval(frame['locals']['In']['value'])
  File "python3.6/ast.py", line 48, in literal_eval
    node_or_string = parse(node_or_string, mode='eval')
  File "python3.6/ast.py", line 35, in parse
    return compile(source, filename, mode, PyCF_ONLY_AST)