Catch a wider range of exceptions when adding events to event queues

We have observed additional exceptions being thrown from zulip_finish and we
need to make sure that the handler is disconnected from the queue, or else the
event queue will keep throwing exceptions due to the handler being closed.

(imported from commit 59273aa14495216430b9eb1525b2cce230d8913d)

zerver/lib/event_queue.py

@@ -99,7 +99,7 @@ class ClientDescriptor(object):
                                                        queue_id=self.event_queue.id),
                                                   self.current_handler._request,
                                                   apply_markdown=self.apply_markdown)
-            except socket.error:
+            except Exception:
                 logging.exception("Got error adding event to queue %s" % (self.event_queue.id))
             self.disconnect_handler()