libvhost-user: Zero memory allocated for VuVirtqInflightDesc

libvhost-user: Zero memory allocated for VuVirtqInflightDesc

Use a zero-initialized VuVirtqInflightDesc struct to avoid
that scan-build reports that vq->resubmit_list[0].counter may
be garbage value in vu_check_queue_inflights().

Fixes: 5f9ff1eff ("libvhost-user: Support tracking inflight I/O in
shared memory")
Reported-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Xie Yongji <xieyongji@baidu.com>
Message-Id: <20191119075759.4334-1-xieyongji@baidu.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>