The fd is possibly a negative value while it is passed as an
argument to function "close". Fix the check to the fd.
Fixes: ed8132e7c912 ("net/tap: move fds of queues to be in process private")
Cc: stable@dpdk.org
Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>