client: auto-reconnect for 500 errors (tulir#743)

Author: Fizzadar

connectionevents.go

@@ -101,14 +101,12 @@ func (cli *Client) handleConnectFailure(node *waBinary.Node) {
 		// By default, expect a disconnect (i.e. prevent auto-reconnect)
 		cli.expectDisconnect()
 		willAutoReconnect = false
-	case reason == events.ConnectFailureServiceUnavailable:
+	case reason == events.ConnectFailureServiceUnavailable || reason == events.ConnectFailureInternalServerError:
 		// Auto-reconnect for 503s
 	case reason == events.ConnectFailureCATInvalid || reason == events.ConnectFailureCATExpired:
 		// Auto-reconnect when rotating CAT, lock socket to ensure refresh goes through before reconnect
 		cli.socketLock.RLock()
 		defer cli.socketLock.RUnlock()
-	case reason == 500 && message == "biz vname fetch error":
-		// These happen for business accounts randomly, also auto-reconnect
 	}
 	if reason == 403 {
 		cli.Log.Debugf(