Openstack-tripleo-validations fails for ctl-plane-iprange

Issue

• Openstack-tripleo-validations fails with "fatal: [undercloud-0]: FAILED! => {"changed": false, "msg": "The IP range 192.0.2.5 - 192.0.2.24 contains 20 addresses.\nThis might not be enough for the deployment or later scaling."}"

[stack@undercloud-0 ~]$ ansible-playbook /usr/share/openstack-tripleo-validations/validations/ctlplane-ip-range.yaml  -i testinv --user stack

PLAY [undercloud] *************************************************************************************************************************************************************************************************

TASK [Gathering Facts] ********************************************************************************************************************************************************************************************
ok: [undercloud-0]

TASK [Get the path of tripleo undercloud config file] *************************************************************************************************************************************************************
ok: [undercloud-0]

TASK [Gather undercloud.conf values] ******************************************************************************************************************************************************************************
ok: [undercloud-0]

TASK [Check the size of the DHCP range for overcloud nodes] *******************************************************************************************************************************************************
fatal: [undercloud-0]: FAILED! => {"changed": false, "msg": "The IP range 192.0.2.5 - 192.0.2.24 contains 20 addresses.\nThis might not be enough for the deployment or later scaling."}
 [WARNING]: Could not create retry file '/usr/share/openstack-tripleo-validations/validations/ctlplane-ip-range.retry'.         [Errno 13] Permission denied: u'/usr/share/openstack-tripleo-
validations/validations/ctlplane-ip-range.retry'


PLAY RECAP ********************************************************************************************************************************************************************************************************
undercloud-0               : ok=3    changed=0    unreachable=0    failed=1