Description of problem:
boot up guest with a iSO attached via ide/scsi-cd interface, the locked value will changed to true after the cdrom mounted automatically in guest due to the udev rule, but the locked value did not change if i umount it manually.
Also tried it in rhel6.5 that did not hit such issue.

Version-Release number of selected component (if applicable):
host info:
3.10.0-60.el7.x86_64
qemu-kvm-rhev-1.5.3-21.el7.x86_64
seabios-1.7.2.2-4.el7.x86_64
guest info:
3.10.0-60.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
1.boot up guest with a iSO attached via ide/scsi-cd interface.
# /usr/libexec/qemu-kvm -M pc -S -cpu SandyBridge -enable-kvm -m 2048 -smp 4,sockets=2,cores=2,threads=1 -no-kvm-pit-reinjection...-drive file=/home/my-cdrom1.iso,if=none,id=drive-data-disk,cache=none,media=cdrom,format=raw,aio=native,werror=stop,rerror=stop -device virtio-scsi-pci,id=scsi1,bus=pci.0,addr=0x7 -device scsi-cd,drive=drive-data-disk,bus=scsi1.0,id=data-disk
2.check the locked value after the cdrom mounted automatically in guest.
guest ]# mount
...
/dev/sr0 on /run/media/root/CDROM type iso9660 (ro,nosuid,nodev,relatime,uid=0,gid=0,iocharset=utf8,mode=0400,dmode=0500,uhelper=udisks2)
(qemu) info block
...
drive-data-disk: removable=1 locked=1 tray-open=0 io-status=ok file=/home/my-cdrom1.iso ro=1 drv=raw encrypted=0 bps=0 bps_rd=0 bps_wr=0 iops=0 iops_rd=0 iops_wr=0

{"execute":"qmp_capabilities"}
{"return": {}}
{"execute":"query-block"}
{"return": [...{"io-status": "ok", "device": "drive-data-disk", "locked": true, "removable": true, "inserted": {"iops_rd": 0, "image": {"virtual-size": 325482496, "filename": "/home/my-cdrom1.iso", "format": "raw", "actual-size": 325484544}, "iops_wr": 0, "ro": true, "backing_file_depth": 0, "drv": "raw", "iops": 0, "bps_wr": 0, "encrypted": false, "bps": 0, "bps_rd": 0, "file": "/home/my-cdrom1.iso", "encryption_key_missing": false}, "tray_open": false, "type": "unknown"}...]}
3.umount the cdrom manually in guest and check the locked value.
# umount /run/media/root/CDROM
{"execute":"query-block"}

Actual results:
after step 3, the locked value still true after i umount the cdrom in guest.
{"execute":"query-block"}
{"return": [...{"io-status": "ok", "device": "drive-data-disk", "locked": true, "removable": true, "inserted": {"iops_rd": 0, "image": {"virtual-size": 325482496, "filename": "/home/my-cdrom1.iso", "format": "raw", "actual-size": 325484544}, "iops_wr": 0, "ro": true, "backing_file_depth": 0, "drv": "raw", "iops": 0, "bps_wr": 0, "encrypted": false, "bps": 0, "bps_rd": 0, "file": "/home/my-cdrom1.iso", "encryption_key_missing": false}, "tray_open": false, "type": "unknown"}...]}

(qemu) info block
...
drive-data-disk: removable=1 locked=1 tray-open=0 io-status=ok file=/home/my-cdrom1.iso ro=1 drv=raw encrypted=0 bps=0 bps_rd=0 bps_wr=0 iops=0 iops_rd=0 iops_wr=0

Expected results:
it should change to false after umount the cdrom in guest.

Additional info:
# /usr/libexec/qemu-kvm -M pc -S -cpu SandyBridge -enable-kvm -m 2048 -smp 4,sockets=2,cores=2,threads=1 -no-kvm-pit-reinjection -usb -device usb-tablet,id=input0 -name sluo -uuid 990ea161-6b67-47b2-b803-19fb01d30d30 -rtc base=localtime,clock=host,driftfix=slew -device virtio-serial-pci,id=virtio-serial0,max_ports=16,vectors=0,bus=pci.0,addr=0x3 -chardev socket,id=channel1,path=/tmp/helloworld1,server,nowait -device virtserialport,chardev=channel1,name=com.redhat.rhevm.vdsm,bus=virtio-serial0.0,id=port1 -chardev socket,id=channel2,path=/tmp/helloworld2,server,nowait -device virtserialport,chardev=channel2,name=com.redhat.rhevm.vdsm,bus=virtio-serial0.0,id=port2 -drive file=iscsi://10.66.90.100:3260/iqn.2001-05.com.equallogic:0-8a0906-4c41f7d03-453f49b421052a57-s2-sluo-270305-1/0,if=none,id=drive-system-disk,cache=none,format=raw,aio=native,werror=stop,rerror=stop,discard=on -iscsi id=iqn0 -device virtio-scsi-pci,id=scsi0,bus=pci.0,addr=0x4,num_queues=4,ioeventfd=on -device scsi-block,drive=drive-system-disk,bus=scsi0.0,id=libiscsi-system-disk,bootindex=1 -netdev tap,id=hostnet0,vhost=on,script=/etc/qemu-ifup -device rtl8139,netdev=hostnet0,id=rtl8139-net-pci0,mac=00:01:02:B6:40:21,bus=pci.0,addr=0x5 -device virtio-balloon-pci,id=ballooning,bus=pci.0,addr=0x6 -global PIIX4_PM.disable_s3=0 -global PIIX4_PM.disable_s4=0 -k en-us -boot menu=on -qmp tcp:0:4444,server,nowait -serial unix:/tmp/ttyS0,server,nowait -vnc :1 -spice disable-ticketing,port=5931 -monitor stdio -drive file=/home/my-cdrom1.iso,if=none,id=drive-data-disk,cache=none,media=cdrom,format=raw,aio=native,werror=stop,rerror=stop -device virtio-scsi-pci,id=scsi1,bus=pci.0,addr=0x7 -device scsi-cd,drive=drive-data-disk,bus=scsi1.0,id=data-disk