net/vhost-user: Remove unused "err" from chr_closed_bh() (CID 1612365)

The "err" variable was declared but never used within the
chr_closed_bh() function. This resulted in a dead code
warning (CID 1612365) from Coverity.

Remove the unused variable and the associated error block
to resolve the issue.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Jason Wang <jasowang@redhat.com>

net/vhost-user.c

@@ -298,7 +298,6 @@ static void chr_closed_bh(void *opaque)
     const char *name = opaque;
     NetClientState *ncs[MAX_QUEUE_NUM];
     NetVhostUserState *s;
-    Error *err = NULL;
     int queues, i;
 
     queues = qemu_find_net_clients_except(name, ncs,
@@ -317,9 +316,6 @@ static void chr_closed_bh(void *opaque)
     qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, net_vhost_user_event,
                              NULL, opaque, NULL, true);
 
-    if (err) {
-        error_report_err(err);
-    }
     qapi_event_send_netdev_vhost_user_disconnected(name);
 }