Some hardware Redfish services have dropped support for continuously
overriding the boot source when the boot mode is Unified Extensible
Firmware Interface (UEFI). See this discussion:
http://lists.openstack.org/pipermail/openstack-discuss/2020-April/014543.html
A workaround falls back to one-time override, restoring it on every
reboot or power on. [1] However, it does not work, because, per the
Distributed Management Task Force (DMTF) Redfish standard, one-time
override is disabled on the next boot cycle. [2] This fixes that by
explicitly setting the boot source override to one-time every time it is
restored.
[1] https://storyboard.openstack.org/#!/story/2007527
[2] https://redfish.dmtf.org/schemas/v1/ComputerSystem.v1_11_0.json
Story: 2007733
Task: 39897
Change-Id: I6f5a11a77e7b16cdd0d837fdec51c3e9aeea9a31