Fix bare except (googleapis#4250)

Jon Wayne Parrott · web-flow · commit 54b3c981981f · 2017-10-24T15:54:12.000-07:00
diff --git a/api_core/google/api_core/future/_helpers.py b/api_core/google/api_core/future/_helpers.py
@@ -35,5 +35,5 @@ def safe_invoke_callback(callback, *args, **kwargs):
     # We intentionally want to swallow all exceptions.
     try:
         return callback(*args, **kwargs)
-    except:
+    except Exception:
         _LOGGER.exception('Error while executing Future callback.')
