bpo-30624 remaining bare except (#2108)

bpo-30624 / selectors: use bare 'except' clause instead of 'except
Exception'

Lib/selectors.py

@@ -357,7 +357,7 @@ def register(self, fileobj, events, data=None):
             poller_events |= self._EVENT_WRITE
         try:
             self._selector.register(key.fd, poller_events)
-        except Exception:
+        except:
             super().unregister(fileobj)
             raise
         return key