Deletion of disk returns OK but is not removed

After fixing the previous issue this new issue occurred, the disk and client are deleted but reappear after reopening gwcli.

```
/iscsi-target...stiscsi/hosts> ls
o- hosts .......................................................................... [Hosts: 1]
o- iqn.1998-01.com.vmware:internal-appliances-hv-01-4b798644 .... [Auth: CHAP, Disks: 0(0b)]
/iscsi-target...stiscsi/hosts> delete iqn.1998-01.com.vmware:internal-appliances-hv-01-4b798644
ok
/iscsi-target...stiscsi/hosts> ls
o- hosts .......................................................................... [Hosts: 0]
/iscsi-target...stiscsi/hosts> cd /disks
/disks> delete rbd.testimage123
rbd rbd/testimage123 is not defined to the configuration
/disks> delete rbd.imagetest123
ok
/disks> ls /
o- / ................................................................................... [...]
o- clusters .................................................................. [Clusters: 1]
| o- ceph .................................................................... [HEALTH_WARN]
| o- pools .................................................................... [Pools: 1]
| | o- rbd ....................................... [(x3), Commit: 0b/10.2T (0%), Used: 4K]
| o- topology .......................................................... [OSDs: 6,MONs: 3]
o- disks .................................................................... [0b, Disks: 0]
o- iscsi-target ............................................................... [Targets: 1]
o- iqn.2018-01.com.test.iscsi-gw:testiscsi ................................. [Gateways: 3]
o- gateways ...................................................... [Up: 3/3, Portals: 3]
| o- iscsigw01 ....................................................... [10.0.36.21 (UP)]
| o- iscsitest ............................................................. [10.0.36.21 (UP)]
| o- iscsitest2 ......................................................... [10.0.36.22 (UP)]
o- host-groups ............................................................ [Groups : 0]
o- hosts .................................................................... [Hosts: 0]
/disks> cd /
/> cd iscsi-target/
/iscsi-target> clearconfig confirm=true
Clients(1) and Disks(1) must be removed first before clearing the gateway configuration
/iscsi-target> exit
[zxcs@testrbd root]$ sudo gwcli
/iscsi-target> ls /
o- / ................................................................................... [...]
o- clusters .................................................................. [Clusters: 1]
| o- ceph .................................................................... [HEALTH_WARN]
| o- pools .................................................................... [Pools: 1]
| | o- rbd ....................................... [(x3), Commit: 5G/10.2T (0%), Used: 4K]
| o- topology .......................................................... [OSDs: 6,MONs: 3]
o- disks .................................................................... [5G, Disks: 1]
| o- rbd.imagetest123 .................................................. [imagetest123 (5G)]
o- iscsi-target ............................................................... [Targets: 1]
o- iqn.2018-01.com.test.iscsi-gw:testiscsi ................................. [Gateways: 3]
o- gateways ...................................................... [Up: 3/3, Portals: 3]
| o- iscsigw01 ....................................................... [10.0.36.21 (UP)]
| o- iscsitest ............................................................. [10.0.36.21 (UP)]
| o- iscsitest2 ......................................................... [10.0.36.22 (UP)]
o- host-groups ............................................................ [Groups : 0]
o- hosts .................................................................... [Hosts: 1]
o- iqn.1998-01.com.vmware:internal-appliances-hv-01-4b798644 [Auth: CHAP, Disks: 0(0b)]
/iscsi-target>
```