Fix atexit

Author: lzchen

contrib/opencensus-ext-azure/opencensus/ext/azure/metrics_exporter/__init__.py

@@ -58,8 +58,7 @@ def __init__(self, is_stats=False, **options):
                 retention_period=self.options.storage_retention_period,
                 source=self.__class__.__name__,
             )
-        self._atexit_handler = atexit.register(
-            self.shutdown, self.options.grace_period)
+        self._atexit_handler = atexit.register(self.shutdown)
         self.exporter_thread = None
         # For redirects
         self._consecutive_redirects = 0  # To prevent circular redirects