Description of problem:
Incorrect error messages when 2 guests on 1 host pointing at the same disk in non-shareable mode while virtlockd is enabled

Version-Release number of selected component (if applicable):
libvirt-3.9.0-1.el7.x86_64
kernel-3.10.0-766.el7.x86_64
qemu-kvm-rhev-2.10.0-4.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
1. Prepare two guests which use one image without <shareable> element.
 <disk type='file' device='disk'>
      <driver name='qemu' type='raw' cache='none'/>
      <source file='/var/lib/libvirt/images/lmn.qcow2'/>
      <target dev='hda' bus='ide'/>
      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
    </disk>
2. Config /etc/libvirt/qemu-lockd.conf.
    #vim /etc/libvirt/qemu-lockd.conf
    auto_disk_leases = 1
    require_lease_for_disks = 1
    file_lockspace_dir = "/var/lib/libvirt/lockd/files"
    #vim /etc/libvirt/qemu.conf
    lock_manager = "lockd"
3. Service start
    #systemctl start virtlockd
    #systemctl restart libvirtd
4. Start two guest.
    # virsh start lmn
    Domain lmn started
    # virsh start test
error: Failed to start domain test
error: internal error: process exited while connecting to monitor: 2017-11-07T09:53:44.435636Z qemu-kvm: -chardev pty,id=charserial0: char device redirected to /dev/pts/4 (label charserial0)
2017-11-07T09:53:44.437831Z qemu-kvm: -drive file=/var/lib/libvirt/images/lmn.qcow2,format=qcow2,if=none,id=drive-virtio-disk0,cache=none,aio=native: Failed to get "write" lock
Is another process using the image?  

Actual results:
As above descriptions.

Expected results:
# virsh start test
error: Failed to start domain test
error: resource busy: Lockspace resource '9e03fed04cb6a2f32f6624b47d212acb06d97653a02627d824b89fcf74c175bb' is locked

Additional info:
The error messages is expected in the following scenario:
(1)The above test steps in libvirt-3.2.0-14.el7_4.3.x86_64;
(2)Pointing at the same lvm/scsi device in none-shareable mode;
(3)2 guests on 2 hosts pointing at the same disk in none-shareable mode.