Fix to use correct config options for ping_timeout
Fix to use correct config options for ping_timeout

ping_timeout config options under compute group have been
deprecated since 1 year and it has been under new group validation.

Tempest will remove the deprecated config options soon.

This commit use the config options from correct group.

Change-Id: I486fc0bbf5ab77b507568726cc268d92f7a07cf2

openstack/networking-fortinet,openstack/networking-fortinet